Stock exchange operator, NZX, has confirmed it is reviewing recent trading in SkyCity shares, following allegations about trading from New Zealand First leader, Winston Peters.
Mr Peters had wanted the Financial Markets Authority (FMA) to investigate what he said was an apparent surge in the share sales last Friday.
Mr Peters said Parliament had been told that the Government and SkyCity agreed on Friday the company would get no taxpayer money to build a convention centre in Auckland.
He said there was unusually heavy trading of the company's shares that day, despite the absence of a public announcement.
FMA compliance director Elaine Campbell said the NZX had taken up the matter.
She said given the nature of the allegations being made, the authority would update the market when the NZX had completed its review.
Financial analysts have told Radio New Zealand that heavy trading was to have been expected, as Sky City has recently released its financial results.
The analysts said there was no major change in the share price or anything else irregular.
The convention centre in downtown Auckland was supposed to cost just over $400 million, but SkyCity had made a push for up to $130 million more in public money when costs blew out.
The agreement meant the casino operator would most likely revise the building's design to keep within costs and the venue could end up smaller than planned.
Mr Peters said Parliament was told the agreement between the Government and SkyCity was made last Friday.
He said 3.4 million shares changed hands that day, even though there had been no market announcement of the agreement.
Mr Peters said that was 2 million more shares than the trading days before and after Friday.
SkyCity has made no comment.