As 85,000 NSW schoolteachers prepare to strike next week, Premier Dominic Perrottet says their wage hike is among the most generous in the country.

The 24-hour walk-off by public and Catholic school teachers on June 30 will be the third strike in six months.

It is expected to affect about a million families, just a day before two weeks of holidays.

Mr Perrottet accused union bosses of “playing politics with the people of NSW”, saying “it’s completely unacceptable and it’s wrong”, considering teachers will get a 3 per cent wage hike, with the potential of 3.5 per cent the following year.

“We have the highest wage increases of any state in the country … I think where we’ve landed is fair and reasonable, it’s nation-leading,” he said on Wednesday.

Teachers in Victoria had been given a 1.5 per cent increase but were not taking industrial action against the Labor government.

“What I don’t see around the country are protests and inconveniencing parents and school children and I think that’s incredibly disappointing,” Mr Perrottet said.

“It’s been a tough few years but need to ensure that what we do is fair and reasonable.”

He accused the unions of going out of their way to cause “massive inconvenience to parents” by striking on the last day of the financial year when people who ran small businesses were busy.

NSW Teachers Federation and the Independent Education Union NSW/ACT called the joint strike after Tuesday’s budget papers revealed no further offer was on the table.

They argue the deal translates to a real wage cut, with inflation running at 5.2 per cent and forecast to tip over 7 per cent, as schools deal with a teacher shortage that threatens to escalate.

“The government has failed students, and continues to fail students and the teaching profession,” NSW Teachers Federation president Angelo Gavrielatos said.