Revenue has been forced to close its busiest office in Dublin because of an occupation by protesters.
Gardaí are at the scene of the protests at the Central Revenue Information Office on O'Connell Street, which takes around 1,000 calls a day.
Revenue said that it regrets the inconvenience to customers.
25 members of the Campaign Against Home And Water Taxes have chained themselves to chairs and radiators at the office just off O'Connell Street.
"It's just about the Revenue, the taxation policy in this country where extremely super rich people and companies are let off scot-free," said spokesperson for the group Ruth Coppinger.
"And yet again and again it’s the ordinary workers that are being made to pay."