Plaid Cymru leader Leanne Wood said:
"The UK Government is wrong to be punishing workers for the financial mess they and the previous Labour Government has caused.
"The withdrawal of labour by workers and the loss of a day’s pay are never taken lightly so this clearly demonstrates the depth of anger by ordinary people who have already conceded much in the way of pay and conditions in recent years.
"Clearly they have decided that enough is enough. Having been the chair of the Assembly’s cross-party PCS group I understand the level of anger from workers and they have my full sympathy and support.
"Most of today’s plenary activity was shifted to the previous day. Meetings I had planned for my office at the National Assembly building in Cardiff Bay today have been re-located as I will not cross the picket line."