Mr Cleary said he made the decision on Tuesday to spend time with his five children rather than be the face of the campaign in the lead-up to September's federal election.

He said the decision to stand aside was "100 per cent" his and there were "absolutely no issues" between himself and the National Party.

Mr Cleary has five children under seven-years-old. The youngest is eight-weeks-old.

He said it was not until he "actually faced reality" of how busy life as a federal election candidate did he decide to withdraw. "I can always stand as the candidate for Throsby again, but I can't get that time back with my kids," he said.

However, Mr Cleary also said he would continue to be involved with the campaign of the National Party's replacement candidate.

The Southern Highland News interviewed Mr Cleary at 5pm on Monday about his election platform, which focused on getting better outcomes for Throsby by making it a marginal seat.

If Throsby became a marginal seat, Mr Cleary said, whoever was elected in September would have to "earn" votes by pledging to deliver more outcomes to the region.

Mr Cleary said, as the Throsby Electorate Council chairman, he would be involved in preselecting a new candidate for the seat and he planned on having an active role in the campaign.

He said the platform of making Throsby a marginal electorate would still be the focus of the Nationals and the only change would be that he would no longer be the face of the message.

The time frame for selecting a new candidate will be decided by the National Party's head office.

"What actual role I have in the campaign will be determined once we have a new candidate."

The decision became public after Wednesday's edition of the Southern Highland News went to print. As of Wednesday morning, Mr Cleary's campaign website and Twitter account were both offline.

NSW Nationals state chairman Niall Blair said Mr Cleary's decision was not a surprise.

He said it was based on family and there were no issues between Mr Cleary and the party.

"He'd spoken to me about it in my capacity as chairman," he said. "He is an important part of the National Party and the Southern Highlands."

Mr Blair said a new candidate would be announced once pre-selection closed and there was candidacy "interest from the Highlands".