The company, formerly Shell, is owned by infrastructure investor Infratil and the New Zealand Superannuation Fund.
In a statement, the owners said while no firm decisions had been made, they had asked Z Energy to work towards a possible listing of 40% to 60% of the company in the third quarter of this year.
Infratil chief executive Marko Bogoievski said at the time of purchase, Z Energy had the challenge of moving off the Shell global platform, new capital investment priorities and the challenge of executing countrywide branding.
''Now, nearly three years on, these have been met and Z Energy has strong cashflows, a good dividend outlook and growth options, which would suit a wider investor audience.''
Craigs Investment Partners broker Chris Timms estimated Z Energy had a book value of around $1 billion, which meant any float would raise between $400 million and $600 million.
The owners had said they would each retain a 20% to 30% stake in the company after listing.
''This listing will be fairly well received. It makes sense to go to the market now. If they had tried to do this three years ago, they would have struggled because of the diverse ownership of the company before it became Z Energy. It is a natural progression.''
NZ super fund spokesman Matt Whineray said the listing would be beneficial for New Zealand's capital market.
The fund's investment in Z Energy had performed well, with the asset benefiting from increased capital investment, strong branding and a focus on customer service.
As a result, Z Energy represented a larger proportion of the fund that it did at the time of purchase. A partial listing appealed as a way of diversifying the fund's investment portfolio, he said.
At January 31, Z Energy was the $21 billion fund's second-largest New Zealand investment, making up 2.4% of the total fund.
