Upper Hunter by-election: date set for by-election in Upper Hunter after Michael Johnsen's resignation

State Upper Hunter Nationals MP Michael Johnsen quit this week in the wake of allegations he offered a prostitute $1000 to come to parliament house for sex.

He's also alleged to have exchanged a series of lewd text messages with the same woman while sitting in the parliamentary chamber, and sent her a sexually explicit video.

The allegations came after he admitted he was under investigation by NSW police for allegedly raping a sex worker in 2019 in the Blue Mountains.

READ ALSO:

Now, voters in his electorate will head back to the polls for a by-election.

The Legislative Assembly Speaker Jonathan O'Dea announced on Thursday the state by-election would be held on May 22.

The National Party has held the marginal seat since the 1930s, but NSW Premier Gladys Berejiklian this week said she expected the Coalition to lose it.

Mr Johnsen held the Upper Hunter electorate by just 2.2 per cent, with reports Labor and the Shooters Fishers and Farmers Party are now expected to make a play for it.

The seat stretches to Quirindi in the north, covering Willow Tree, Murrurundi, Merriwa and down to Singleton in the south, and Gloucester in the east.

Mr Johnsen became an MP after the 2015 election, and won his second term in 2019. He was also the Parliamentary Secretary for Agriculture, but quit the role and parliament on Wednesday.

The outgoing MP released a lengthy statement confirming his exit and said he made the decision with a heavy heart, and described himself as "an imperfect human".

"A serious allegation has been made against me via the process of parliamentary privilege and the immediate leaking of my name to the media associating it with the speech - an action with clear political intent by that member of parliament and her support team to politically and personally damage me outside of the due process already underway," he said.

"I vehemently deny this allegation, which is devastating, unfair and unfounded.

"I will fight the allegation and expect to have my name cleared, as it just didn't happen. However the needs of the electorate come first and that is the approach I have always taken, often at great personal sacrifice such as the role of a member of parliament demands and many may not fully realise."

The early exit of Mr Johnsen - more than half-way through the state four-year term - has left the premier with a minority government.

- with Newcastle Herald and AAP.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: