The competition watchdog has cleared the path for Australian fuel retailer Ampol to acquire Z Energy.
The Commerce Commission said the clearance is subject to Ampol selling its existing New Zealand operation, Gull Petroleum.
Commission chairperson Anna Rawlings said it was satisfied that if Ampol sold Gull, its $2 billion acquisition of Z Energy was not likely to dent competition in New Zealand.
Ampol announced earlier this week that it was planning to sell Gull to Australia's Allegro Funds for $572 million.
But the commission stressed it had not yet approved the sale of Gull to Allegro.
Under the divestment terms, Ampol is required to sell Gull within a specified timeframe and to a purchaser approved by the commission.
"We are aware that Ampol has entered into an agreement to sell Gull to Allegro Funds. In granting clearance, the commission is not approving Allegro as the purchaser of Gull," Rawlings said.
"Under the terms of the divestment undertaking, Ampol is required to obtain separate, formal approval from the commission for Allegro to acquire Gull. We will consider such a request once it is received."
If the commission did not approve Allegro as the purchaser of Gull, it said the terms provided a process to sell Gull to another company approved by the regulator.