He is stepping aside so that he can contest pre-selection for the South Coast seat of Gilmore.

The 47-year-old had been named as one of the contenders for the NSW Liberal leadership in the wake of Gladys Berejiklian's sensational resignation on Friday due to an investigation by the corruption watchdog ICAC.

However, he no longer has eyes for the state's top job.

"After almost 20 years serving in the NSW Parliament, today I have made the decision to nominate for local preselection for the federal seat of Gilmore," he said.

"There has been a lot of speculation over the past few weeks, but I will be resigning as Transport and Roads Minister this week and as the Member for Bega by the end of the year.

"I am very conscious of getting our community out of COVID lockdown and working alongside our small businesses to rebound as strongly as we can."

He said he was "heartbroken for my long-time friend Gladys Berejiklian" and felt that by retiring from State Cabinet and NSW Parliament, he would provide an incoming leader the opportunity to fill this position.

Now Transport and Roads Minister, Mr Constance has previously held the positions of Disability Services Minister and Treasurer.

He had been interested in a path to Federal Parliament for several years.

Last year, he threw his hat into the ring for the seat of Eden-Monaro only to withdraw 24 hours later after John Barilaro, his state colleague and NSW Nationals leader, denigrated him in a front-page news story.

The seat of Gilmore is now held by Labor's Fiona Phillips with a margin of 3 per cent.

She won it in a race against Liberal candidate Warren Mundine; who was parachuted into the local election race by Prime Minister Scott Morrison.

The sitting member Ann Sudmalis had chosen not to contest the seat.

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