The Green Party is calling for an audit of Treasury's Debt Management Office (DMO)because of the way its staff have been accepting free lunches, dinners and other hospitality from banks.
Papers released under the Official Information Act show Treasury officials have accepted more than 200 gifts in the past year, mostly from the major banks.
The freebies include 98 free lunches and 60 free dinners, tickets into the rugby, golf, theatre and wine-tasting events.
The papers say officials were also hosted at 16 rugby games and attended golf, theatre and wine-tasting events; most of them courtesy of banks and investment firms.
Westpac extended corporate hospitality in 37 instances including paying for 10 lunches, 13 dinners, nine rugby games, three golf games and one ticket to the theatre.
ANZ provided 29 freebies including 18 lunches, six dinners, one ticket to the Wellington Cup and two to the Toast Martinborough festival.
Deutsche Bank, BNZ, Barclays, HSBC and law firm Chapman Tripp also provided hospitality.
The DMO accepted more than two thirds of the gifts, with just six staffers responsible for the bulk of that.
'Conflict of interest'
The Greens say there's a conflict of interest because the DMO's job is to minimise the cost of borrowing for the taxpayer, while the banks are trying to maximise it.
Treasury is bound to comply with the State Services Commission code of conduct which states that public servants must decline gifts or benefits that place them under any obligation or perceived influence.
Any gifts, benefits and hospitality offers that are worth more than $50 must be registered.
Mr Norman says with Finance Minister Bill English overseeing government debt, he wonders if he is comfortable with the level of corporate hospitality provided to the office.
Mr English is in Samoa and his office says he has no comment. Neither does the State Services Minister.
Treasury Secretary Gabriel Makhlouf says his staff accept the hospitality offered by major banks and other corporates in order to build good working relationships.
Mr Makhlouf told Checkpoint there is no risk of staff being influenced.
"Now the fact is that our borrowing's done on pretty well established and international levels of transparency. We have a public tender process; only the lowest bids are accepted and we publish the results, and nobody's told me, or as far as I am aware my predecessor,
that we are borrowing at higher levels of interest than we need to."
He says he plans to review the guidelines for gifts of hospitality to ensure they are robust.
Mr Makhlouf says the events are attended by other bank clients.
The Labour Party says New Zealand is lucky that its state sector is accountable for the level of corporate hospitality it receives.
Labour's state sector spokesperson Ruth Dyson says she is comfortable the public service has gift registers and is accountable for them.