Hundreds of employees at the conciliation service Acas have staged a one-hour strike over their pay row.
More than 600 members of the Public and Commercial Services (PCS) union working in offices across the UK and the Acas helpline stopped work between 10:30am and 11:30am in protest at a 2% offer on Friday.
This year's pay increase was due on 1 August and follows a 10-month delay on last year's 2007 pay increase.
PCS general secretary Mark Serwotka said: "It is ironic that the people who help resolve industrial disputes have themselves been pushed into taking industrial action by unacceptable delays and a pay offer that represents a real-terms pay cut."
"The situation at Acas is symptomatic of the government's policy towards public sector pay, which is creating financial misery for hardworking families. It is time that the government reviewed its pay policy and paid a fair wage to the people who keep this country working," he said.
A spokesperson for the Department of Business, Enterprise and Regulatory Reform said strike action was unnecessary because talks were ongoing.
Although largely government-funded, Acas is a non-departmental body, governed by an independent council.