Tax office staff in Northern Ireland are set to take a "mass extended lunch" for two hours in a protest at sickness policy today.
It follows a walk out yesterday afternoon, with Public and Commercial Services union (PCS) staff now refusing to work overtime, use private cars for work or "cut corners".
The PCS said members at Revenue and Customs offices would go to work at 10am and take a "mass extended lunch" for two hours from 11.30am.
A HMRC spokeswoman said the service was disappointed at the decision to disrupt the working day over "simplified" but unchanged sickness policy.
PCS branch secretary Barney Lawn said: "If you have had a clean sick record for 10 years and you had a bout of illness, then you would be facing potential disciplinary procedures which could lead to dismissal."
He claimed medical appointments now must be taken outside working hours.
The HMRC spokeswoman said it had not changed its sickness policy, merely simplified it.
She added: "HMRC is disappointed with the decision to disrupt the working day and will do everything it can to maintain services to the public.
"The wellbeing of our staff is of paramount importance, however HMRC's attendance record must be tackled urgently in the interests of both staff and customers."