A key reason for Fremantle being sent to Geelong for their qualifying final at the weekend may have become clearer yesterday when the Labor Party committed funding for the next stage of the Simonds Stadium redevelopment.

Corio and Corangamite Labor MPs Richard Marles and Darren Cheeseman promised the first $5 million of what Geelong hopes will become up to $45 million of Federal funding for the $80 million fourth stage.

Mr Cheeseman told local media the final at the stadium was proof of its potential.

"We can see the benefit to the community already with the first final in Geelong for over 100 years this weekend," he said.

The five-stage plan is expected to cost a further $140 million.

Corio is considered a safe Labor seat but Mr Cheeseman's seat of Corangamite is marginal.

The Cats were hoping for funding commitments from both major parties in the lead-up to the Federal election.

Stadium "content" - the number of major events at a venue - is a critical part of viability to justify government funding.

Dockers fans Brad and Kelly Hanson, who are travelling to Geelong to watch the game, believe it should have been played at a bigger venue. "It should have been promoted as a blockbuster instead of being shoved out to the suburbs," Mrs Hanson said.

The AFL raised eyebrows on both sides of the nation and infuriated fans in WA with its plan to play the final in Geelong, a backflip from a July 17 declaration that Simonds Stadium would not host a final. The MCG and Etihad were to be the Melbourne venues.

AFL chief executive Andrew Demetriou argues the second-placed Cats "earned" a home final and four finals being in Victoria this weekend was a unique set of circumstances that warranted playing in Geelong. In future it was likely finals would be at other boutique venues such as Metricon Stadium and Skoda Stadium, the home grounds of Gold Coast and Greater Western Sydney, he said.

But the Cats played only seven of their 11 home games in Geelong this year. Three were at Etihad Stadium and a blockbuster against Hawthorn was at the MCG.

AFL crowd and revenue estimates for Saturday's final, used to justify the decision to play at Geelong and not Etihad Stadium, were based on estimates more than 12,000 lower than the crowd Etihad Stadium management expected.

It is understood the AFL gave a crowd estimate as low as 28,000 for the game if it was played at Etihad for a net return of $700,000.

If the game was in Geelong, where the league was offered a "clean" stadium to work with, the league estimated a 30,000 crowd would generate a net return of $2 million.

Fremantle and Geelong drew a crowd of 44,000 to the MCG when they played in the first week of September last year as the sixth and seventh-ranked teams.

Etihad Stadium management told The West Australian last week they expected the game would draw a similar crowd on Saturday if played at their venue.

Fremantle argued that about 40,000 people were likely to turn up to Etihad Stadium and the income deficit would be only about $500,000.