The opposition has slammed an "appalling overspend" on signage at a government ministry head office.

David Cunliffe, Labour's science and innovation spokesman, said the money spent on the sign outside Ministry of Business, Innovation and Employment (MBIE) headquarters in central Wellington was disgraceful.

"It's an appalling overspend on signage and it's offensive to those staff who've been let go in the restructure for cost-saving reasons," Mr Cunliffe said this morning.

It has also emerged that the stated cost of the sign has blown out. The cost was initially revealed to be $43,490, but it turns out the true cost was closer to $70,000.

MBIE admitted to the spend-up on the sign the same day it announced at least 56 job cuts.

"It's a definite lapse of judgement by officials and it's also a failure of oversight by the minister Steven Joyce."

Mr Cunliffe said it was "poor form" for economic development minister Mr Joyce to blame officials.

"I think he should review how the decision was made and who made it, and put in place demonstrable steps to ensure that that kind of overspend cannot happen in future," Mr Cunliffe said.

"I think the amount for the sign is over the top and I've spoken to MBIE's chief executive and made that clear," Mr Joyce told Stuff.

The stone sign stands outside the newly refurbished art deco building that houses MBIE -- formerly the Defence headquarters -- on Stout St.