A new survey that reveals corruption is on the rise in New Zealand has been labelled a wake up call.

The Public Service Association is urging the government to take New Zealand's slip in corruption rankings seriously.

Transparency International's Corruption Perceptions Index 2016 has ranked New Zealand as the fourth least corrupt country in the world - that's our worst ranking since 1998.

PSA national secretary Glenn Barclay said there have been murky processes around the Auckland Convention Centre deal and Serco's handling of Mt Eden Prison.

He said there needs to be greater transparency in the awarding of contracts and full public consolation where services are privatised.

Chair of Transparency International New Zealand Suzanne Snively said it's concerning we're going backwards, she thinks it's possible the drop could impact who wants to trade with us.

"Our reputation is very high, when you do focus groups analysis of New Zealand what they think about New Zealand is that we're place of integrity, a great place to do business - that's what gives us an edge."

Ms Snively said it shows how much we undervalue our integrity.

"One of the things it gives us this asset, is that it gives us infinite possibilities as a nation. So much of what we do we're constrained by distance by resources by our tax base, but integrity is infinite."

The index shows we've dropped two places to be the fourth least corrupt, with Denmark, Finland and Sweden taking out the top three spots.

New Zealand has previously topped the index seven times