"We should not limit our efforts to 2018. We need to be talking about a longer framework for our cooperation," Faleh said before a meeting between OPEC and non-OPEC countries in Muscat.
This is the first time OPEC kingpin Saudi Arabia explicitly calls for extending a 2016 deal between oil producers to cut back production to combat a global oil glut.
OPEC and non-OPEC countries signed a landmark agreement in November 2016 to cut output by 1.8 million barrels per day to fight huge oversupply and lift sagging crude prices.
"I am talking about extending the framework that we started -- which is the declaration of cooperation -- beyond 2018," Faleh told reporters.
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But Faleh said the new framework for cooperation might differ from the current agreement and its production quotas.
"It does not necessarily mean sticking barrel by barrel" to the same agreement, which has helped a healthy rebound in oil prices to around $70 a barrel.
It would mean "assuring stakeholders, investors, consumers and the global community that (the agreement) is here to stay".
Faleh said oil producers have not yet achieved their target of reducing world stocks to normal levels and striking a balance between supply and demand.