Unions and bosses could be able to negotiate long-term pay agreements before mega-projects start if a federal Labor government is elected.

Bill Shorten made a pitch to big business in Perth on Wednesday, promising he would consider changes to workplace laws to allow long-term “greenfields” bargaining.

He said massive projects which are expected to last beyond three years would fall under the plan.

The proposal would benefit major resources efforts, with Western Australia the key beneficiary.

The Labor leader said he wanted to deliver “win-win” outcomes for business and workers

Mr Shorten, who is a former Australian Workers’ Union national secretary, reflected on his negotiating experience.

“I’ve spent my adult lifetime negotiating and delivering win-win outcomes for employees and employers,” he told business leaders.

“I also understand that achieving win-win outcomes is only possible when everyone plays by the same rules.”

While not backing away from describing Saturday’s election as a referendum on wages and the cost of living, Mr Shorten said he wanted to bring unions and business to the table.

“I think this country works best when we work together,” he said.

He said modest wage rises would help the overall economy, noting the current rate of zero per cent inflation was unhealthy.

“An anorexic economy is not the shape of a healthy economy.”

Mr Shorten said average wage rises under the coalition had been 2.2 per cent, while under Labor governments pay had gone up 3.6 per cent.

“That doesn’t mean the sky is going to fall in,” he said, stressing the average was not his nominated number on wages growth.

Mr Shorten said controversial businessman and Senate candidate Clive Palmer played “fast and loose” with the rules.

“Thanks to the preference deal he’s done with Scott Morrison, Clive Palmer can turn up on day one with a political IOU almost as big as his ego,” the opposition leader said.

He committed to holding a summit between unions and big and small business in Perth in early June.