The demands from the Public Service Association (PSA) come on the back of industrial action and strikes from unions representing nurses, teachers, public transport staff and other government employees, all of whom seek a pay rise.

NSW Premier Dominic Perrottet has hinted at relief on wages in the state budget on June 21, but has also warned it will be unlikely to fully appease all of the unions and their various demands.

Public sector pay increases have been capped at 2.5 per cent per annum since 2011.

"Now (workers) are being asked to cop inflation too - something has to give," PSA general secretary Stewart Little said.

The PSA represents thousands of workers across the public sector, ranging from prison officers, park rangers, school support staff, ServiceNSW workers, and civilian police employees.

The cap operates as a wage cut in real terms due to current high inflation, Mr Little said.

He has written to Mr Perrottet seeking a 5.2 per cent wage increase and says the government has until the end of Monday to respond with an acceptable offer.

Without one, public sector workers will strike on Wednesday next week, Mr Little warned.

He said increasing public sector pay would boost the economy.

"Public sector wages get pumped straight back into the economy and stimulate growth, particularly in regional NSW," he said.

"They also set the benchmark for wages generally."

"As the largest employer in the country, Premier Perrottet has more power to fix Australia's wage crisis than any other leader," Mr Little said.

Australian Associated Press