Corrections Minister Judith Collins has accused prison union bosses of "living a jet-set lifestyle" on the taxpayer after they received $127,000 in expenses from her department in one year.

Ms Collins said she was particularly concerned the Corrections Association was using public money to travel after hearing it had amassed a $2 million fund from its membership that could be used for a strike.

She said the Corrections Department was paying for unionists' flights, rental cars and restaurant meals as well as salaries while they conducted union business for prison officers.

But the union said the spending was justified and Ms Collins was playing "dirty pool" in releasing it, and challenged her to do the same with the department's executives.

Ms Collins gave the information to the Herald yesterday and used it to attack the union. "I am concerned this money is being used to fund a jet-set lifestyle for union bosses".

She had ordered her departmental chief executive Barry Matthews to find out if he could put a stop to the funding.

She said union president Beven Hanlon was using the funding "to trot around the country and make critical comments about Corrections officers".

She said this was extremely inappropriate given the officers were paying union dues.

Ms Collins said she had also heard the union had $2 million in savings "but are being paid by the taxpayer to do the job most union members thought they were paying fees for".

Ms Collins said she learned of the spending after an Official Information Act request from Labour MP George Hawkins covering expenses from the entire department. Labour said the release was a "pre-emptive strike".

Mr Hanlon said the money came from the Correction Department calling meetings and paying for the Corrections Association to come.

If the union called the meeting, he had to take annual leave and his expenses were met by the union.

He asked why Ms Collins had not released the chief executive's or general manager's expenses.

"It's a bit of dirty pool, but not unexpected, unfortunately."

Labour law and order spokesman Clayton Cosgrove said there were "constitutional questions" about Ms Collins selectively releasing parts of an Official Information Act request, while the MP who asked for it was still waiting for an overdue response.

Taxpayer funding of prison union chiefs
* Airfares: $32,215
* Rentals and taxis: $3163
* Accommodation: $6226
* Salaries and backfill: $86,122
* Total: $127,726