A NSW government promise to address public sector wages in next month's budget won't stop public school teachers striking for 24 hours.
Education Minister Sarah Mitchell urged the union to cancel Wednesday's strike after directing her department to delay wage negotiations as part of a new teachers' award before the Industrial Relations Commission until after the June 21 budget.
"So the onus is really now on union bosses to make decisions about what they want to do," she said on Tuesday.
Ms Mitchell said delaying wage arbitration while continuing other negotiations showed the government was working in good faith.
NSW Teachers Federation President Angelo Gavrielatos says the strike will go ahead as teachers seek pay rises of five to 7.5 per cent while struggling with their workload.
He called on parents to support the action to ensure their children are taught by qualified teachers, warning of an unsustainable situation in education with more than 70 per cent of teachers considering new careers.
The union executive voted for the 24-hour strike after the government failed to negotiate further when industrial action was suspended last term, Mr Gavrielatos said.
Premier Dominic Perrottet said his government had been fair and reasonable throughout negotiations with multiple public sector unions undertaking industrial action.
The action was part of a political campaign to cause havoc across NSW for the benefit of the Labor Party, he said.
"We're working through this issue as part of the budget process," Mr Perrottet said.
"Allow the government to do it and don't disrupt our parents, and particularly our children."
The premier has promised to address public sector wages in the budget but also acknowledged that may not be enough to appease the various unions and their frontline workers.
Mr Gavrielatos said there was no guarantee the government would make good on its promise.
The union has been seeking negotiations since February last year and won't wait until it sees what's in the budget before striking.
"We have been very patient," Mr Gavrielatos said.
He dismissed temporary changes to assessment and accreditation requirements that could ease teacher workloads announced on Tuesday as "gimmickry".
Mr Gavrielatos said children's education was at risk because pay rises were needed to attract more people to the profession and to retain existing staff.
He accused the government of trying to address shortages by making it easier for people to become teachers, saying qualifications and standards were being lowered under the guise of modernising the profession.
Mr Gavrielatos declined to predict how many teachers would strike on Wednesday but expects a high turnout amid unprecedented anger across the profession.
Ms Mitchell said striking teachers would lose a day's pay.
There would be limited supervision in schools for children whose parents needed to work but they should check on the arrangements first.