The Financial Markets Authority confirmed it had received complaints. Photo: 123RF
Several banks involved in arranging government bond issues and in trading them have denied any suggestion of market manipulation.
The alleged manipulation related to bonds issued in August 2022 cost taxpayers $33 million, the New Zealand Herald reported.
The Financial Markets Authority (FMA) confirmed it received complaints but declined to give any other details.
RNZ Business contacted the banks authorised by Treasury to trade the bonds - ANZ New Zealand, BNZ, UBS and Westpac.
Two outright said they had not been contacted by the FMA, one categorically denied any involvement, and one declined to talk under instructions from within the bank.
The FMA gave little away in response to questioning from RNZ Business.
"Generally, the FMA does not comment on whether or not it has received complaints or is investigating a specific entity," a spokesperson said.
"However, we can confirm we've received complaints regarding the trading of government bonds in the past five years."
It refused to comment further about the timing, the identity of the bank and the outcome of the complaints.
In Australia, it was reported the finance sector regulator was investigating the ANZ Group over Treasury-bond issuance.
The FMA said it was aware of the proceedings.