Members of the Public and Commercial Services union (PCS) in Merseyside struck for three hours on Monday 5 March.
The strike was part of an attempt to stop the transfer of 100 workers from local job centres to centralised call centres.
29 job centres and two existing call centres were affected by the action.
Carillion workers launch more strikes
Carillion workers at Great Western Hospital in Swindon will take a further five days of strike action from 8 March, followed by another 7 days from 17 March.