Premier Colin Barnett used the first day of state parliament yesterday to reveal his government's plan, saying that while the state was presently prosperous it could not continue as it was.

"A shortage of skilled labour means that there is a limit to how much construction activity can occur at any one time," he said.

"It is also difficult for both economic and social infrastructure to keep up, in spite of projects such as Pilbara Cities and the new hospitals being built."

The constraint would be further compounded by the expected additional 750,000 people moving to WA by 2026.

"Unless something changes, the crunch will come on state government finances," Mr Barnett said.

"The Liberal National Government is committed to ensuring future generations of Western Australians have a legacy from this historic period of economic development, built predominantly on the significant but finite resources available to us at present."

Details of the future fund would be outlined in the May budget and legislation introduced later in the year.

Also in his annual Premier's Statement, Mr Barnett outlined the government's legislative agenda for the last parliamentary year before the state election on March 9, 2013.

Legislation to allow Sunday trading, which was introduced to parliament yesterday, will be the priority. New laws regulating lobbyists, a Bill limiting prostitution in the suburbs, and anti-association Bill to crack down on organised crime gangs also were priorities.

Mr Barnett said Liberal Party MPs would be allowed a conscience vote on the Prostitution Bill and called for other all MPs to be granted the right because it would raise ethical and moral issues.

Opposition Leader Mark McGowan will deliver his in-reply speech today.

He has already criticised the idea of a future fund while the state was carrying $15 billion in debt.