UPDATED: 5.11PM Inland Revenue's defending itself against claims its workers take sick days when they're not sick.

LISTEN ABOVE: CTU president Richard Wagstaff and Kirk Hope from Business New Zealand chat to Larry Williams

IRD figures show its employees take more than twice the number of sick days than the national average - according to Southern Cross that's 4.7 days a year.

In a statement, the department said its sick leave numbers are consistent with those of other similar public sector organisations.

IRD said its sick leave management aims to create an environment where people turn up to work ready, motivated and engaged to do their best.

Taxpayers' Union boss Jordan Williams said there's a culture in state services of people taking sick days when they're not sick.

CTU president Richard Wagstaff said it's wrong to assume that means IRD staff are throwing sickies.

He told Larry Williams there's no evidence of that.

"Organisations that are large, organisations that have sick leave provisions in their employment agreements, and organisations where you have many permanent staff as opposed to people on 90 day trials or casual staff, tend to take more sick leave than small work places, that's no surprise".

But the Public Service Association said while some collective contracts are more generous, that's not true.

A PSA spokesperson was unsure as to how representative the Southern Cross Wellness In the Workplace survey figures were.

She said only 113 businesses were surveyed, with their staff making up only 6.5 per cent of New Zealand workplaces.