Nationals MP Adrian Piccoli has confirmed he will quit state politics forcing a third by-election in NSW.
Premier Gladys Berejiklian said the former education minister, who was dumped from the frontbench earlier this year, would leave a strong legacy in state parliament.
"Adrian Piccoli has been a Member of Parliament since 1999 and has been a tireless advocate for both the electorate of Murrumbidgee and more recently the electorate of Murray," Ms Berejiklian said in a statement.
Mr Piccoli is the second Nationals MP to quit parliament this year, following member for Cootamundra Katrina Hodgkinson's early exit.
His retirement will trigger a by-election in the seat of Murray - the fifth in NSW this year.
The government faces upcoming by-elections in Cootamundra, as well as Blacktown following the retirement of former Labor leader John Robertson.
Gosford and Manly were also re-contested in April with Labor and the Liberals each retaining their respective seats.
Nationals leader John Barilaro said the party would miss Mr Piccoli's experience, but claimed it provided an "opportunity for renewal".
"I thank Adrian for his extraordinary service and wish him all the best for his future endeavours," he said in a statement.
The Shooters, Fishers and Farmers party has already announced it will field candidates in both Cootamundra and Mr Piccoli's seat.
Mr Piccoli is reportedly taking a job with the University of NSW.
