Greens leader Richard Di Natale has described the Federal Government as "extremist" for not taking tougher action to reduce emissions, while dismissing the Prime Minister's claims the Greens were apologists for farm-invading vegans.

Key points: Greens leader Richard Di Natale says Scott Morrison has misrepresented his views the vegan activists who trespassed on farms

Greens leader Richard Di Natale says Scott Morrison has misrepresented his views the vegan activists who trespassed on farms Senator Di Natale says he has great sympathy for farmers targeted by the activists

Senator Di Natale says he has great sympathy for farmers targeted by the activists Prime Minister Scott Morrison says the Greens are a bigger threat to the economy than the United Australia Party

In an interview with 7.30 on Monday night, Prime Minister Scott Morrison said the Greens posed a greater threat to the future of the Australian economy than the United Australia Party — with whom the Liberals have struck a preference deal.

He accused the Greens leader of supporting vegan activists who broke into farms, of advocating death taxes and pursuing a reckless renewable energy target.

"Scott Morrison will say or do anything to hold onto the job," Senator Di Natale told 7.30 on Tuesday evening.

"The real extremists are the Liberal/National Party and we desperately need to turf them out."

The Greens leader cited the Prime Minister bringing a lump of coal into Question Time while the planet faced a "climate emergency", as well as "racism and division at the heart of this government".

Asked specifically about the accusation that he supported vegan activists trespassing on farms, Senator Di Natale repeated his previous comments that anyone breaking the law should face consequences.

He said the Prime Minister's accusations were a "disgraceful" lie, and that he had "great sympathy" for farmers who had been targeted.

"He should apologise for misrepresenting my views on this," Senator Di Natale said.

"Of course we condemn some of those activities. If people are going to break the law they should face consequences."

Greens hope to toughen climate policies through Senate

Senator Di Natale was asked if his party would respect Labor's mandate if the Opposition won the election, or whether the Greens would use a potential balance-of-power position in the Senate to make policy demands.

"People also vote differently in the Senate ... because they want to hold governments to account," he said.

"If Bill Shorten is elected as the next prime minister, it will be on the back of Greens preferences."

He said the Greens would be unapologetic about using their numbers in the Senate to toughen climate policies, criticising Labor for bringing a "weaker" set of climate promises to the election than they had in 2016.

He said the Greens would resist the approval of the Adani coal mine in Queensland and the use of fracking for gas extraction in the Northern Territory.