The United Nations' former climate change czar has intervened in the Australian election, publicly backing four female independent candidates and calling out "appalling inaction in Canberra" on climate change.

Key points: Christiana Figueres led the global negotiating process that culminated in the 2015 Paris climate change agreement

Christiana Figueres led the global negotiating process that culminated in the 2015 Paris climate change agreement She has thrown her support behind four female independents whose key opponents are Liberals

She has thrown her support behind four female independents whose key opponents are Liberals Speaking to a Sydney forum, Ms Figueres said the Paris Agreement required countries to bring forward the most ambitious possible national targets every five years

Christiana Figueres led the UN's global negotiating process that culminated in the 2015 Paris climate change agreement, and is now a climate leader at the World Bank.

She has thrown her support behind Zali Steggall, who is standing against former prime minister Tony Abbott in the NSW seat of Warringah, Wentworth MP Kerryn Phelps, Mayo MP Rebekha Sharkie and the MP for Chisholm, Julia Banks, who resigned from the Liberal Party and is contesting the nearby seat of Flinders as an independent.

Ms Figueres said the four women "set out strong policy platforms and longer-term vision for what it would take for Australia to take its rightful place as a leader in the global fight against climate change".

She condemned what she called "the ridiculous climate wars in Australia that have led to a very damaging climate and energy policy vacuum for more than a decade".

"This inaction is putting us at war with a climate that has no more room for atmospheric pollution," Ms Figueres said.

"No other policy issue has been plagued by such partisan attacks, nor heralded the repeated fall of Australian prime ministers."

"Extreme elements from both sides of the political spectrum have frustrated sensible, forward-looking policies founded in what must be our most important guide — the science."

The Coalition has been contacted for comment.

Independents praised for their 'courage'

Two of the four candidates — Dr Phelps and Ms Steggall — on Tuesday attended a meeting in Sydney of Mission 2020, which was established after the Paris Agreement to drive global action on climate change in order to cap greenhouse gas emissions and limit global temperature rises to 1.5 degrees Celsius.

MP for Wentworth Kerryn Phelps, with Zali Steggal, who is standing against Tony Abbott in the NSW seat of Warringah, at the Mission 2020 meeting in Sydney on May 7, 2019. ( Stephen Long )

Speaking via video link, Ms Figueres praised the four independents for "your courage and leadership in having put climate action and clean energy at the forefront of your respective campaigns.

"As mothers, we all share a deep sense of responsibility to make right what is currently going very wrong."

After the meeting Dr Phelps told the ABC that she thought it "enormously significant that a world leader on climate change has backed the independents who are backing action on climate change."

"We have a moment in time when can put in place policies that will make a difference to the future of our planet," Dr Phelps said.

Business leaders, clean energy lobbyists and investors advocating stronger climate change action and policy signals briefed the candidates at the forum.

"We have been hearing today from investors … and people who understand the science of climate change better than anyone in the country and they are telling us that not only is there an urgent need for action, but governments can no longer afford to delay their action," Ms Phelps said.

"There is a dire message from the science on climate change but there is a positive message about where we can go," Zali Steggall added.

"With clear policy from government the market will take care of it and we have great potential."

Cost of inaction

Ms Steggall also responded to concerns raised during the campaign about the cost of Labor's proposed climate change policies.

"The price of climate change action is nothing compared to the price of inaction."

Speaking to the Sydney forum, Ms Figueres said the Paris Agreement required countries to bring forward the most ambitious possible national targets every five years.

"Whoever is elected needs to be prepared to bring a revised 2030 target to the table in the next 12 months," she warned.

The former UN climate change leader dismissed arguments that action in Australia to limit global warming would make little difference to global climate change.

"The fact that Australia only contributes 1.5 per cent of global emissions is not an excuse not to act," she said.

"If every country adopted that stance, we would be on track to oblivion. Your island neighbours in the Pacific would go under the waves."

"We look hopefully to the Land Down Under for a watershed election that sparks a new wave of climate leadership."