Oil giant Mobil wants to buy out Z Energy's stake in jet fuel ventures used to supply Auckland Airport.
The Commerce Commission said Mobil had applied for clearance to acquire up to 100 percent of Z Energy's stake in the Wiri-to-Auckland pipeline and the Auckland Airport Joint User Hydrant Installation (JUHI).
But Z Energy said it had not struck a deal with Mobil.
The Wiri-to-Auckland pipeline delivers jet fuel to the airport from the storage facility at Wiri, which is then stored at the airport at the JUHI. Both assets are jointly owned and operated by BP, Mobil and Z.
Mobil's application to the Commission said both jet fuel agreements contained pre-emptive rights if a current owner underwent a change of control.
It comes as the High Court in Wellington today gave clearance for the Z Energy to be bought out, after shareholders last month approved a takeover bid by Australia's Ampol.
Mobil said the completion of the deal would trigger the change of control provisions in both jet fuel agreements and require Z to give Mobil and BP the right to acquire its ownership interests.
It said the total percentage of ownership interests Mobil could ultimately acquire would depend on BP's position on exercising its own pre-emptive rights.
Z Energy chief executive Mike Bennetts said: "We don't have any arrangements with Mobil at the moment to divest our aviation assets. I'm not really able to comment on why they made an application".
He said Z Energy was "very committed" to the aviation space and about 20 percent of its sales went to the aviation sector.
If Mobil is given the all clear by the competition watchdog, it would pave the way for the company to become the majority owner of both assets.
Mobil said the decision to exercise its pre-emptive rights was motivated by its intentions to modernise the agreements and how the Wiri-to-Auckland pipeline and JUHI are owned and operated.
It said it wanted to facilitate new entrants into the jet fuel markets at Auckland Airport, encourage future investment and address concerns raised by the government inquiry into the Auckland fuel supply disruption in 2017.
The Commission said it would give clearance if it was satisfied a merger was unlikely to dent competition in the market.