NSW police have warned they will come down hard on any anti-social or drunken behaviour at Wednesday night's State of Origin rugby league game in Sydney.

"The majority of Origin fans enjoy these matches without incident," Assistant Commissioner Peter McErlain said.

"Nonetheless, I make no apologies when coming down hard on a select few who want to break the law," he said in a statement.

NSW Police say "Operation Nocke" will involve a highly visible police presence at ANZ Stadium and on public transport, including the public order and riot squad and dog squad.

Last year, 40 people were ejected from the stadium and six were banned from returning to the stadium for 12 months.

Police are expecting a crowd of 70,000 for Wednesday's game, the first in the three-match series.

Spectators are urged to leave their car at home and catch public transport.

And on the 30th anniversary of the State of Origin concept, the two female premiers of NSW and Queensland have added a new twist to the annual bet on the series outcome.

The traditional bet involving the losing state flying the winner's flag - either on Sydney Harbour Bridge or Brisbane's Story Bridge - started in 1999 with a wager between Queensland Peter Beattie and NSW Premier Bob Carr.

However, Queensland Premier Anna Bligh says she and NSW's Kristina Keneally have decided to add to te competition, with the losing premier to host a footy breakfast fundraiser to benefit breast cancer.

The proceeds will be shared equally between breast cancer charities in each state.

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