Labor and the Greens say Foreign Minister Julie Bishop is trying to diminish the outcome of climate talks that will not even take place until next year.

They say Ms Bishop is trying to ensure there is no useful outcome after next year's climate change talks in Paris.

Greens leader Christine Milne and Labor's environment spokesperson Mark Butler are both at the same climate talks that the Foreign Minister and Trade Minister are attending in Peru.

Ms Bishop and Trade Minister Andrew Robb have reportedly argued that carbon emission targets beyond 2020 should be legally enforceable.

But it is well known in the international community that countries such as the US and China will reject the imposition of any legal obligations.

“You can't help thinking that ... the sudden commitment to a legally binding agreement is nothing other than a way of ensuring there isn't an outcome in Paris,” Greens leader Christine Milne said.

Mr Butler said all the legal talk was designed to take away from the fact that the Climate Change Performance Index has rated Australia as the worst performing industrial country, as it works to remove its own emissions targets.

“I think this question of legal enforceability is a red herring,” Mr Butler said.

“I fear that Julie Bishop is stoking this issue as a major distraction from the fact that the Government has nothing to take to these talks.”

It is true that some fine details of future talks are less important than some of the other topics at the Lima conference.

Significant issues include finding ways for contributions from rich and poor countries to cut carbon emissions be equal, relative to the country in question.

Delegates will talk for over a week on a new deal to limit rising atmospheric gas emissions, which is expected to be signed in Paris next year.