Unions NSW secretary Mark Lennon said up to 10,000 workers gathered outside the NSW parliament in Macquarie Street on Wednesday to send a "clear message to Prime Minister Tony Abbott and NSW Premier Mike Baird that they don't like their agenda on workplace relations and privatisation".

The rally was one of many staged in capital cities around the country as part of a national day of action.

The Sydney protesters chanted slogans including "NSW not for sale" and "They say cut back, we say fight back".

A series of unions representing nurses, teachers and transport and electrical trade workers spoke out against the privatisation of the electricity network, hospitals and TAFE. They also protested against cuts to penalty rates.

Members of the Health Services Union, the Transport Workers Union, the NSW Nurses and Midwives Association, the NSW Teachers Federation, the CFMEU and other unions waved flags and placards with messages including "Stop the NSW Power Sell-Off" and "Save TAFE".

Electrical Trades Union NSW secretary Steve Butler said the March 28 state election would provide an opportunity to "throw the mongrels out".

ACTU secretary Dave Oliver said the rights of workers were under attack from the Abbott government and employers.

"The Coalition government is using the Productivity Commission inquiry into rights at work in an attempt to cut penalty rates, abolish the minimum wage, bring back unfair individual contracts and swing even more power to the employers," he said.

"Australians did not vote for cuts to Medicare, $100,000 university degrees, slashing the public sector, abolishing the minimum wage, cuts to penalty rates and rights at work."

ACTU president Ged Kearney said the Abbott government was also "on notice".

"We made our voices heard in the Victorian and Queensland elections with one-term Coalition governments and we can do it again with the Abbott government," she said.