UPDATED: 9AM

The Government is unlikely to consider launching an inquiry into petrol companies until Z Energy's application to acquire Chevron NZ is complete.

Labour's energy spokesperson Stuart Nash is calling for an inquiry, following a doubling in petrol profit margins over the past four years.

Finance and Expenditure Select Committee chairman David Bennett agrees petrol prices are a concern for everyone. He indicated the committee would consider a case if Mr Nash puts one forward.

"It's a matter for the committee to make a decision depending on the facts and information they have," he explained.

Despite this Energy and Resource Minister Simon Bridges said it would be inappropriate for him to take further action before the Commerce Commission's report into Z Energy's application is released.

He is hopeful the report will provide insight into the nature of competition in the market.

Bridges said MBIE has been working with the industry to improve margin reports after he warned petrol retailers they were "on notice" in February.