The Perrottet government’s state wage cap is facing a big test as drivers refuse to man trains and tens of thousands of public sector school teachers stage their first strike in a decade in support of big pay rises to keep up with other professions.

Union members of the 90,000 public teachers in NSW will stop work for 24 hours on Tuesday in defiance of anti-strike orders to pressure the government to increase salaries by between 5 and 7.5 per cent a year to deal with huge staffing shortages.