The outspoken NSW Nationals leader will miss next week's parliamentary sittings and won't return to his role for up to four weeks.

Mr Barilaro's office confirmed he was temporarily stepping down to take time off for his wellbeing and mental health.

In a statement, Premier Gladys Berejiklian said Mr Barilaro had told her of his decision on Friday afternoon.

"I have offered him any support he may need," she said.

"I wish John and his family all the best during this time."

His deputy Paul Toole has been installed Acting Deputy Premier and state party leader.

Mr Toole praised his Nationals colleague for putting his hand up to take a break, and said he looked forward to his return.

"People need to know it's ok to say when you are having a tough time - and that's exactly what John has done," he said in a statement.

"The NSW Nationals support each other and stick together."

It means he'll likely miss an October 6 cabinet meeting in which the state's vexed koala protection policy was expected to be debated.

Mr Barilaro put himself in the firing line last week after threatening to implode the coalition government if concessions were not made over the policy.

He backed down when the premier gave him an ultimatum that Nationals MPs support the government or its ministers be sacked from cabinet.

Mr Barilaro was unrepentant for his actions after he survived a no-confidence motion in parliament on Wednesday, angering Liberal colleagues when he refused to rule out threatening the coalition again.

He later committed to honouring the coalition until the 2023 state election.

The Nationals are concerned changes to the Koala Habitat Protection State Environmental Planning Policy limit land use on farms and the ability to rezone areas for development.

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Australian Associated Press