WARM conditions are forecast for Saturday afternoon's preliminary final between West Coast and Melbourne at Optus Stadium.

With the contest taking place in the middle of the day to allow Melbourne's players to get back to Victoria swiftly if they win, temperatures could top 25 degrees during the game.

Other than the potential warmth in the west, weather is not expected to have a huge impact on either preliminary final.

The forecast for the MCG on Friday shows only the very slight possibility of any rain, which is sure to please the capacity crowd that's expected.

With Tigers and Magpies club members snapping up all available tickets within two hours, public sales were cancelled for Monday afternoon.

AFL members' tickets sold out within 30 minutes on Tuesday morning.

Melbourne Cricket Club members will hold the possibility of a 100,000 crowd in their hands, with up to 13,000 seats available for walk ups on Friday.

Security will be tight as it has been for all major games at the MCG this year, with parking in Yarra Park limited to pass holders.

While it will be Optus Stadium's biggest game in its short history, the venue confirmed its security arrangements would be the same, and it was "business as usual".

FINALS FORECAST

Richmond v Collingwood, Friday September 21 at the MCG, 7:50pm AEST MCG

Partly cloudy. Five per cent chance of any rain.
Min 8. Max 18.
Tickets: Exhausted, other than 13,000 MCC walk ups.
Parking: No public parking, limited for passholders/disabled
Transport: https://www.ptv.vic.gov.au/
Channel 7 commentators: Bruce McAvaney, Brian Taylor, Wayne Carey, Cameron Ling, Daisy Pearce, Matthew Richardson
Simulcast on Fox Footy and Telstra AFL Live App

West Coast v Melbourne, Saturday September 22 at Optus Stadium, 1:20pm AWST

Partly cloudy. 20 per cent chance of any rain.
Min 12. Max 26.
Tickets: Exhausted
Parking: Limited. Fans advised to take train or walk across bridge from city
Transport: https://www.transperth.wa.gov.au/
Channel 7 commentators: Luke Darcy, James Brayshaw, Matthew Richardson, Peter Bell
Simulcast on Fox Footy and Telstra AFL Live App