Brownlow arrests shock former AFL umpire

Umpiring great Shane McInerney is dismayed by the accusations of a Brownlow Medal betting ring, saying it's devastating for his colleagues.

A current AFL field umpire is among four men arrested over dubious betting activity around this year's Brownlow voting.

Victoria Police detectives from its Sporting Integrity Intelligence Unit arrested and interviewed four men on Monday.

Three of the men are expected to be charged and the fourth was released pending further inquiries.

At this stage, authorities have no information to suggest the outcome of the votes were impacted.

McInerney, who was an AFL field umpire for a record 502 games, said they put great importance on their pivotal role in the Brownlow Medal.

"Shocked is one word - disappointed, in fact probably beyond that, it's actually devastating news," the two-time grand-final umpire told SEN.

"It's probably particularly devastating for the existing AFL umpiring list.

"Certainly in my time, the list greatly valued the integrity of the Brownlow Medal. They saw their responsibility ... as an absolute privilege.

"So to have this news come out yesterday, (it's) shocking."

The umpires award Brownlow votes on a 3-2-1 basis after each game and there is tight security around those details until AFL chief executive Gillon McLachlan reads them out on Brownlow night.

The league emphasises the lengths that are taken around the integrity of the voting and McInerney said this was drilled into the umpires annually.

"There was a lot of instruction, particularly in the pre-season ... each year," McInerney said.

"One of the senior umpires would talk about the process and talk about the importance, the time required post-game to ensure we get the right outcome.

"Part of that conversation would be the integrity people, just keep us across what the different challenges were with particular sports betting and other integrity issues."

The AFL released a statement on Monday with general counsel Andrew Dillon saying after this year's Brownlow the league had been made aware of potential suspicious activity by one of their betting agency partners.

The AFL's integrity unit worked with the betting agency to gather further information alongside Sports Integrity Australia and Victoria Police.

The AFL was making no further comment on Tuesday, given no charges had been laid.