NSW premier nervous over by-election

The NSW premier is nervous about fighting another by-election triggered by the snap resignation of Nationals MP Katrina Hodgkinson with the Shooters and Fishers Party now circling.

Gladys Berejiklian on Tuesday insisted she wasn't surprised by the early resignation of the Cootamundra MP, but admitted to being worried about the untimely poll.

Ms Hodgkinson on Monday revealed she would leave Macquarie Street at the end of August after almost 20 years in parliament.

It was time to move on to something new, she said.

For the Berejilkian government, however, Ms Hodgkinson's resignation means more of the same; a fourth by-election this year.

The premier on Tuesday told reporters she would have preferred Ms Hodgkinson continue in her role but argued the resignation wouldn't reflect badly on her government.

In April, the Liberals retained the northern Sydney electorates of Manly and North Shore, while Paralympic gold medallist Liesl Tesch picked up the seat of Gosford for Labor.

Ms Hodgkinson said she was worn out after 18 years as a member of parliament.

"I just feel that it's time, It's always going to be difficult," Ms Hodgkinson told Macquarie Radio.

But she also admitted she had been disappointed by the government's approach to local government mergers which affected councils in her electorate.

The mergers were a "desktop exercise", Ms Hodgkinson said.

The Shooters and Fishers Party hopes to see a similar swing away from the Nationals in the Cootamundra by-election as occurred in Orange in late 2016 when their candidate, Philip Donato, prevailed.

"It's going to be more difficult for us in the seat of Cootamundra, there's no doubt about that," Shooters and Fishers MLC Robert Borsak told reporters on Tuesday, adding they were yet to preselect a candidate.

Mr Borsak believes Ms Hodgkinson is quitting politics because she was treated poorly by her party and government.

"We respect her as a person, no question of that, but I think she's been let down rather badly by her own party and by this government and we intend to make as much of this opportunity as we can."

Opposition Leader Luke Foley said he would talk to party members in Cootamundra, but the ALP may not contest the seat.

"It's one of the safest conservative seats in the state," he said.