The Prime Minister says a law student is "free to try" to change Government policy or the law with her case against the Government saying not enough has been done to combat climate change.

Sarah Thomson's judicial review against the Minister of Climate Change in the High Court in Wellington claims the Government's Paris Climate Agreement targets don't go far enough - but the Government argues its targets are fair.

For more on this story, watch 1 NEWS at 6pm. Source: 1 NEWS

Bill English today said that "the targets for New Zealand are already pretty challenging" and added that Ms Thomson is "of course free to try like anyone else to influence Government policy or the law in this respect".

This is the first time in New Zealand history where a case has been taken against the Government over climate change, and while Ms Thomson told 1 NEWS she is nervous ahead of the review, she is also confident.

"I've got the backing of amazing lawyers and scientists," she said.

"I see it as an ordinary person taking a stand, you know?