A Wellington Inland Revenue office has been closed until tomorrow, following a threatening phone call to the national call centre just before midday.
An Inland Revenue spokesperson said as a precautionary step, its Hawkestone Street office in Thorndon had been closed.
The Tauranga office was also closed but has reopened. Extra security has been put in place at the Wellington office.
Police said they are following positive lines of enquiry.
Extra security was also in place at Inland Revenue's office in Featherston Street in Wellington, which remained open.