The Canadian company, which operates Papua New Guinea's sole oil refinery, has come under public pressure throughout the year as higher fuel prices have taken hold.

Under the interim agreement between InterOil and the Independent Consumer and Competition Commission, wholesale and retail margins are set annually while changes to the import price parity system are done monthly.

This month's IPP has petrol rising 9.6%, diesel rising 12% and kerosene rising 13.6% from May.

The ICCC said the rise in the IPP levels was due to May's record Singapore Tapis crude prices and increased shipping freight charges.

"I reiterate, neither the ICCC, the Government, nor InterOil is responsible for the powerful worldwide forces that determine the price of crude oil on the international market," Jasper said in a statement.

"The forces of international supply and demand are running riot and fuel prices are shooting sky-high."

In a May report, Goldman Sachs analysts led by Arjun Murti said the possibility of oil reaching $US150-200 a barrel was increasingly likely over the next 5-24 months.

Jasper said many oil industry insiders were taking Goldman's prediction seriously.

He said each month PNG customers will have to face rising fuel bills with latest indications signalling the days of cheap plentiful fuel appear to be gone for good.

"Each month more and more of our capital is being tied up in crude oil shipments or in storage tank stockpiles awaiting refinement."