Saudi Energy Minister Khaled al-Faleh said Monday that oil producing nations could start discussing in June when to raise output, though OPEC is expected to maintain curbs until it clears a global glut.

OPEC and its partners agreed last week to keep a lid on output for all of 2018, a strategy that aims to reduce a global excess in supply that has pushed oil prices lower and left a huge hole in the finances of producer nations.

"We will not alter our course in the second half of the year," Faleh told reporters in Riyadh after a meeting with US Energy Secretary Rick Perry.

"However, the outlook for when we will hit the balanced market will be clearer in June and we will start thinking of what to do in 2019.

"The intent is not overnight to... flood the market."

Nations that supply a majority of the world's oil agreed last week to maintain production curbs of 1.8 million barrels per day.

So far, helped by an improving global economy, the strategy has worked, helping oil prices climb from less than $30 in early 2016 to around $60 now and reducing bloated inventories to more normal levels.

But the producers agreed to review in June "progress achieved towards re-balancing of the oil market" and make "adjustments" if necessary.

Separately, Saudi Crown Prince Mohammed bin Salman has voiced the need to stabilise markets following a meeting with Perry.

"The crown prince affirmed the kingdom's keenness to stabilise energy markets and supply them in a sustainable manner to serve the interests of energy producers and consumers," the official Saudi Press Agency said on Monday.