NOT since the Liberal education minister Terry Metherell slashed 2500 teaching positions 22 years ago has there been such a large and angry gathering of NSW public service workers.

Yesterday's protest in The Domain against the state government's industrial relations legislation turned out to be bigger than even the organiser, Unions NSW, had hoped, with 35,000 teachers, health workers, police, firefighters, prison guards and government departmental clerical employees converging for a very public attack on the Premier, Barry O'Farrell.

And the secretary of Unions NSW, Mark Lennon, has promised there is more to come.

''This is going to be a long campaign … it will be a political campaign, it will be a campaign we will take out to the community and, as always, there will be industrial aspects to it as well,'' he said.

It took the protesters more than an hour to reach Hyde Park from The Domain, a route that took them directly past Parliament in Macquarie Street.

Responding to a comment on Twitter that accused the Premier of hiding in his office, Mr O'Farrell tweeted: ''I was in the balcony listening to the speeches in the Domain.''

The Minister for Finance and Services, Greg Pearce, accused unions, Labor and the Greens of hypocritical scaremongering in organising the protest. ''[They] know that Labor introduced the wages policy in 2007 and that the policy is required to get the state's finances back on track,'' he said. ''Yet they are silent on these facts.''

Mr Pearce said by joining the protest, teachers had defied the Industrial Relations Commission, which had ordered them on Wednesday not to strike.

The president of the NSW Teachers Federation, Bob Lipscombe, said there was ''no joy in the hearts'' of teachers in striking.

At the core of the public sector's grievances is a pay rise capped at 2.5 per cent per a year, while inflation is expected to hover around 3.6 per cent. Any additional pay rises will only be considered if offset by productivity gains through improved efficiency or cutting costs.

Public sector workers have also lost the right to have pay and working conditions cases heard independently by the commission.