A goal in each half by Jermain Defoe and another from Joe Cole sealed the fate of the gallant third division side, who were unlucky to go behind on the stroke of half-time.
The only blemish on an otherwise competent, professional performance by the Hammers was the late dismissal of John Moncur following a lunge at Chris Byrne, who was lucky to stay on the field himself after his reaction to being lifted off the floor by the Hammers midfielder that provoked an untidy skirmish involving an unnecessary number of players on both sides.
If West Ham went to Cheshire with any fear of seeing Macclesfield add their name to a long list of lower league clubs who have inflicted humiliation on them in the past, there was no sign of it at Moss Rose.
On a lush even pitch that played remarkably well considering earlier concerns about the possibility of a postponement due to the freezing conditions in the build-up to the game, Glenn Roeder's men passed the ball well and kept plenty of possession, with Trevor Sinclair particularly threatening on the left flank.
Despite the continuing absence of Paolo Di Canio and Michael Carrick, plus the loss again of Fredi Kanoute (flu), Hammers controlled much of the game although give Macclesfield a lot of credit for applying some good first half pressure that yielded a succession of corners and dangerous crosses.
In fact, Richard Tracey should have been awarded the first goal of the game, but his headed effort in the 4th minute was wrongly ruled out for offside - the TV cameras confirming that Sebastien Schemmel had just played him onside. Town were also unlucky when Lambert's free-kick was deflected up and on to the crossbar.
The deadlock was broken in the 45th minute, when Cole fed the ball wide to Schemmel whose early, low cross to the near post was met by Defoe, who nipped in front of Tinson to net with a fine first time finish from six yards.
Defoe and Moncur tested Town keeper Steve Wilson with early second half strike as the visitors tightened their grip on an entertaining game. West Ham's resolute back four restricted Macclesfield to a couple of half chances for Lee Glover, but David James - sporting yet another new hairdo - was always equal to anything the Silkmen could fire at him.
After Cole sent a right foot volley fizzing past the post, Defoe scored his second in the 72nd minute out of nowhere. Receiving a short pass from skipper Don Hutchison, the England under-21 striker found the far corner of the net with a delightful, curling effort from 20 yards.
That knocked the stuffing out of former Hammer Kevin Keen and his team-mates and it was no surprise when Cole made it 3-0 just minutes after Moncur departed.
Reacting quickest to some hesitancy in the home defence, the in-form Cole produced a typically clever dummy and shimmy before planting his right-foot shot just inside the far corner of the net.
Although Macclesfield were a credit to Division Three of the Nationwide, always trying to play football, West Ham had too much class and got stronger as the game progressed.
Indeed, in time added on, Defoe spurned a good chance to complete his hat-trick when he drove wide.
4 - Macclesfield have a goal ruled out when Tracey is adjudged to be offside from a near-post flick on.
7 - After good work from Hutchison and Sinclair on the left, Moncur's shot from the edge of the penalty area is charged down by a defender.
8 - Midfielder Byrne sees his dipping left-foot shot fly just over the crossbar.
9 - Sinclair's ball over the top of the defence almost releases Defoe, but keeper Wilson is quick to clear.
13 - Cole wastes the best chance of the match so far as he collects a return pass from Schemmel and bursts into the area before firing his shot just over the bar.
15 - With keeper Wilson stranded on the touchline, Kitson's quick thinking throw sets up Sinclair on the edge of the box, but his effort bounces wide of the target.
19 - Byrne gallops into the area unchallenged to meet Adams' cross but sees his header deflected over for a corner.
22 - Tracey's curling effort fromt he edge of the area is well held by James.
28 - Schemmel booked for kicking the ball away.
31 - Lambert's venomous free-kick from 25-yards out is safely clutched to his chest by James.
33 - Good work by Defoe on the right sets up Moncur, whose fierce shot is well saved by Wilson.
34 - The impressive Sinclair is again at the heart of things as he finds Defoe, who turns and curls a wicked effort just inches wide of the post.
36 - Another blistering free-kick from Lambert is deflected by the wall and skims off the top of the crossbar for a corner.
41 - Sinclair's deep left-footed cross is headed over by Kitson.
43 - Keen's cross causes panic in the Hammers defence as James fails to clear and Hutchison heads out from under his own crossbar before Moncur clears.
45 - GOAL! After withstanding some heavy pressure, the Hammers take the lead when Schemmel's teasing low cross from the right is superbly flicked in by the predatory Defoe at the near post. Macclesfield Town 0 West Ham United 1.
Added time: 2 minutes.
Half-time: Macclesfield Town 0 West Ham United 1.
47 - Defoe almost grabs his second, latching on to an intelligent through-ball from Hutchison but seeing his hooked effort palmed away for a corner by Wilson.
48 - Moncur's scorching effort from 25 yards appears destined for the top right hand corner until Wilson superbly tips the ball away and then pounces on the follow-up to deny Hutchison.
56 - Cole's sweeping pass out to the left finds Sinclair, who cuts inside but sees his effort deflected over the bar for a corner.
65 - Macclesfield have their first real effort of the second half as Lambert's instant header drops just wide of the post.
65 - Substitution for Macclesfield, McAvoy replaces Tracey.
68 - Schemmel's corner is cleared to the edge of the penalty area, where Cole is waiting to unleash a blistering right-foot volley that flies just wide of the target.
72 - GOAL! The vital two-goal cushion finally arrives as Hutchison feeds Defoe some 30 yards out and the England under-21 striker advances forward a few yards before curling a beautiful right-foot shot past the despairing dive of Wilson. Macclesfield Town 0 West Ham United 2.
72 - Substitution for Macclesfield, Ridler replaces Priest.
82 - Controversy as Moncur is sent off for two bookable offences in the same incident. The Hammers midfielder fouls Byrne and is then involved in a clash with the player before a melee erupts. Dailly and Adams both booked.
84 - Substitution for West Ham, Foxe replaces Hutchison.
85 - GOAL! Joe Cole rounds off a thoroughly professional performance and secures the Hammers' place in the fourth round as he pounces on a loose ball outside the area, dribbles past a couple of weak challenges and plants a low 18-yarder into the bottom corner. Macclesfield Town 0 West Ham United 3.
90 - Repka booked for foul on Lambert.
Added time: 3 minutes.
90 - Defoe runs clean through on goal but misses the chance to grab a hat-trick as his shot dribbles wide.
Full-time: Macclesfield Town 0 West Ham United 3.