The visitors made a game of it for much of the first half but had no answer once the hosts - who look to be Marr's main rivals in the promotion race - got into their stride.
It is "as you were" at the bottom of the league with all three teams below Irvine also losing, but as next week's visitors Helensburgh were the victors in one of those games, Irvine will not now be able to overtake the Ardencaple side should they win.
The match started routinely enough, with the visitors edging in front on 3 minutes with a Ross Bryan penalty after Ruchin Filander's run deep into the GHK half was illegally halted. Minutes later however the hosts squared the match through Bryan's counterpart David Reed, after Kevin Lang was sent to the sin bin for an alleged stamp on an opponent.
Irvine edged back in front on 10 minutes after the hosts knocked the kick-off on and were penalised at the resulting scrum, but the visitors immediately returned the compliment, leaving the scores tied at 6-6 after 12 minutes.
It was briefly 14 v 14 when GHK hooker Gordi Reid became the second player of the afternoon to be sent to the bin, but Irvine were unable to capitalise on his absence upon Lang's return and were punished shortly afterwards when the hosts claimed the opening try on 32 minutes.
The danger looked to have passed when a forward pass brought an end to a promising spell of GHK possession deep in the Irvine half, but the hosts forced a free kick at the resulting scrum which they took quickly, with number 8 Michael Borthwick forcing his way over in the corner. Reed's conversion took the score to 13-6 in the home side's favour.
Reed edged the home side further in front on 38 minutes with another penalty as they continued to turn up the heat, before their pressure finally told on the cusp of half time when full back Aubrey Horton crossed in the left corner. Reed was unable to add the conversion, leaving the half time score at 21-6.
GHK continued to dominate after the break and Reed added another penalty on 48 minutes to take the score to 24-6.
Irvine tried to respond and began to enjoy more possession as they sought the try that would give them some kind of foothold in the game but it was the hosts who struck next on the hour. Ross Bryan missed touch with a penalty and Ian Spiers knocked the return clearance on, and from the resulting scrum the hosts worked the ball wide to winger Callum Ruxton who needed no second invitation. Scrum-half Mike Aird, taking over the kicking duties, converted to make it 31-6.
The hosts clinched the bonus point on 68 minutes. The GHK forwards mauled the ball down the left from their own half, aided by a series of penalties for collapsing which culminated in the sin-binning of hooker Michael Kirk - although Kirk maintained that the referee had got the wrong man - and finally forced their way over in the left corner to make it 36-6, with Reid claiming the touchdown.
The visitors might have had a consolation when Craig Hobson intercepted and made a dangerous run into the GHK half, but he lacked support and the move broke down.
It was left to the hosts to have the last word in injury time when they forced a penalty deep in the Irvine half, from which the GHK forwards once again bullied the ball over the line for a second try of the afternoon for Michael Borthwick, which went unconverted, leaving the final score at 41-6.
It was also a bad day at the office for Marress, who suffered their second defeat in succession, 38-25 at home to leaders Greenock Wanderers. Alan Nugent scored two of their three tries, with prop Ewan Callaghan claiming the other and Stuart Tracey adding two conversions and two penalties. They now sit third in the league, eight points behind Greenock and seven behind second-placed Garnock, who won at Clydebank. They are next due to entertain Cambuslang.
GHK -- A Horton; A Powell, A McLay, D Hoffmann (capt), C Ruxton; D Reed,
M Aird; C MacPhee, G Reid, C McLay, P Ritchie, F Hastie, G Hollerin, A Patrick,
Subs: O McInroy, F McLeod, H Lough, A Shedden.
IRVINE -- K Hobson; C Hobson, A Spiers (capt), C Lang, J Carson; R Bryan,
R McVey; B Auld, M Kirk, S Docherty, I Spiers, R O'Neill, A Lang, R Filander,
Subs: T Wright, A Thomson, G Gibson, S Cook.