ST KILDA coach Alan Richardson believes "the noise of affirmation" from partisan home crowds in Perth can influence umpires' decision-making.
The Saints were on the wrong end of a lopsided free kick count (23-8) in Saturday night's clash against West Coast at Domain Stadium.
In the last five times the Saints have travelled to Perth to take on West Coast, the cumulative free kick count stands at 114-60 in the Eagles' favour.
Although Richardson refused to blame the latest discrepancy for the 19-point loss, the Saints' coach said umpires subconsciously favoured home teams in Perth due to the parochial crowd.
"From my perspective, I call it 'the noise of affirmation'," Richardson told Fox Footy on Monday night.
"Our game is very grey, particularly from an umpiring perspective and … particularly with issues like holding the ball. You go in there, 'Did he duck? Did he have prior opportunity? Did he dispose of the ball incorrectly?' The umpire has got to weigh all this up.
"And then there's this incredible noise that potentially gives the umpire some form of affirmation or if you're an opposition player, there's no noise.
"My experience is that it's the no calls that are the bigger issue. We were frustrated and disappointed with some of the sloppy stuff in terms of tackle, but on the flip side, some of those that I thought (were) like-for-like we could've got, we didn't get."
Geelong coach Chris Scott agreed with Richardson's views.
"No one can argue that the situations that he's describing aren't happening," Scott said.
"It would be enlightening for the fans and footy people in general to know the umpires are across it as well.
"What they find a little bit harder to explain is the numbers, which are ridiculous.
"So the umpires say, 'Look, we acknowledge that it's different and we don't think it has much of an impact'. But then you combine it with the numbers and they say, 'Well, actually they're a strange set of numbers', so maybe there's a little bit more to it."
On Monday, umpires coach Hayden Kennedy told AFL.com.au's Whistleblowers program that he was satisfied with the standard of umpiring following a review into the Eagles-Saints game.