Prison officers should have the right to take strike action as a matter of "respect and trust", the TUC's annual conference has heard.
The walkout by prison officers took ministers by surprise
Thousands of staff walked out last month in a row over pay, which led to ministers taking legal action against the Prison Officers' Association.
The union's general secretary, Brian Caton, said members should be able to strike if they are "being abused".
The government and the POA are to hold talks in an effort to end the pay row.
'Respect and trust'
Mr Caton told TUC delegates in Brighton he could not understand why a Labour government was refusing to give prison officers the right to withdraw their labour.
He said: "We are not saying we want to go on strike, but we want the right to do that if we are being abused.
"We want mutual understanding, respect and trust."
Bob Crow, general secretary of the Rail Maritime and Transport union, which organised a London Underground strike last week, supported the POA's demands.
The TUC conference called for prison officers to be given the right to restrict or withdraw their labour.
Prison officers took strike action against the government's decision to give public sector workers a 2.5% pay rise in two separate stages.
Prime Minister Gordon Brown insists this is essential to curbing inflation.
But TUC delegates voted overwhelmingly on Tuesday for a campaign of "co-ordinated" industrial action this autumn if the pay settlement is not improved.