Oil prices are expected to extend a rebound thanks to improved global growth, a drop in stockpiles and fewer drilling rigs, Kuwaiti Oil Minister Ali al-Omair said.

"We have reached a stage where a drop in oil prices is unlikely," he said, cited by the official KUNA news agency on Tuesday night.

The Organization of Petroleum Exporting Countries (OPEC), which earlier this month left its output target unchanged, has seen a decline in excess crude supply in the international market which will push prices up, Omair said.

There has also been a drop in rig count and crude inventories, he added.

As a result of a production glut and a weak global economy, crude prices plummeted by more than 60 percent from June 2014 to January before recovering part of the losses.

Oil prices extended their gains in Asia Wednesday on expectations of a decline in US crude inventories and robust economic data from the eurozone.

US benchmark West Texas Intermediate for August delivery was up 12 cents at $61.13 a barrel and Brent climbed 11 cents to $64.56.

Omair said that the oil sector had requested additional funding of more than one billion dinars ($3.3 billion) for the Gulf state's new refinery after bids by international consortia exceeded budget estimates.

He said that the estimated cost of the 615,000-barrel-per-day (bpd) Al-Zour refinery would now surpass 5.0 billion dinars ($16.5 billion), up from the initial cost of $13.2 billion.

He said the new estimates would be presented to the Supreme Petroleum Council, the highest decision-making body on oil, to secure approval for the additional funds.

Together with the $12-billion project to upgrade two of the existing three refineries, Kuwait plans to raise its output of refined products to 1.4 million bpd from 930,000 bpd currently.

Kuwait, a member of OPEC, pumps around 2.8 million barrels of oil a day.