One of the largest government ministries has revealed how much the controversial refit of its Wellington headquarters actually cost.

Almost $70,000 was spent on an exterior sign at the Ministry of Business, Innovation and Employment, which brought expenditure at the ministry under the spotlight.

It has emerged that the total refit cost was nearly $16 million dollars - $2.2 million under budget.

However a large screen cost more than $140,000.

CEO David Smol says MBIE must be careful about all expenditure now and in the future.

"I'm in the process of putting in place arrangements that ensure that we strengthen the scrutiny of sensitive areas of expenditure in our overall responsibility for stewardship of public money."

Smol said a direct report will be made to him on any areas where 'careful judgement' is required.