The Commerce Commision is calling for submissions on how it should determine the actual cost of retail phone companies accessing Chorus' copper wires.
In December last year, the corporate regulator decided that the average wholesale price of what it calls Chorus' unbundled copper local loop should be $23.52 a month from December next year, based on benchmarking against other countries.
This is different, but related to, the commission's 5 November decision about the pricing of broadband over copper wires, which has sent Chorus' shares plummeting.
The commission says five companies, Chorus itself, Telecom, Callplus, Orcon and Vodafone have applied for the current review.
Chief executive of Callplus, Mark Callander, says the benchmarked price was set too high which is why his company has called for a review.
While the director of external affairs at Vodafone Tom Chignell says his company wants to be involved in the decision-making process.