Brisbane-based Prime announced the acceptances late on Friday, after the New Zealand Stock Exchange had closed, and said the majority shareholders’ acceptance - of their desired 62.5% cash-37.5% bonds mix - meant a substantial security holder notice would be filed shortly. Prime Infrastructure Management secretary Michael Ryan filed that notice with the NZX this morning.

However, the filing of those acceptances comes just a day before the Takeovers Panel investigates whether an arrangement with Sydney-based broker Tricom Equities - to purchase up to NZ$50 million of “excess” bonds from the big three shareholders - contravenes the Takeovers Code that requires all shareholders to be treated equally.

Media reports say the deal could be under threat if the panel finds an association between Prime and Tricom, something which Prime has denied.

Some commentators believe the panel will approve the deal, while others cite links between investment bank Babcock & Brown, its subsidiary Prime Infrastructure, and Tricom as sufficient reason to halt the sale.

Tricom was a co-lead manager of last week's Babcock & Brown float, and is itself a shareholder in Prime.

Prime Infrastructure chief executive Chris Chapman is reported as saying that while Tricom is a material shareholder in Prime, he is unsure whether it holds shares in its own right or as a beneficial owner for other investors in Prime, which has a market cap of A$770 million and many brokers and financial institutions as part of its shareholder base.