Hunt warns against opposing direct action

The Abbott government has warned senators opposed to its direct action policy that blocking the initiative to address climate change in parliament could trigger a constitutional crisis.

Environment Minister Greg Hunt on Tuesday said he was confident the direct action plan would succeed - even though a majority of Labor, Greens and Palmer United Party senators are likely to oppose it - because its funding was tied to the budget.

"The funds will be part of the budget papers, and I doubt that the budget will be blocked unless we're going to be forced into a constitutional issue," Mr Hunt told ABC Radio on Tuesday.

The last time the upper house blocked the supply of government finances was in 1975 - an act which triggered the Whitlam dismissal.

Mr Hunt said the plan had always been to link $1.55 billion for the emissions reduction fund - the centrepiece of direct action - to appropriation bills allowing the government to spend money.

Short of sparking a crisis, this effectively means the government can sidestep upper house opposition to the scheme, including from key crossbench senators controlled by federal lower house MP Clive Palmer.

The mining magnate and Palmer United Party leader, who's likely to control four votes in the Senate, has made it clear he thinks direct action is a "token gesture" and a waste of money.

The government will need the votes of at least six crossbench senators to get the legislation passed.

Mr Hunt said the government respected the wishes of the Senate and would continue to work with its members to pass the bills.

Direct action would achieve greater emissions reductions than Labor's carbon tax, and at less cost, he added.