"It depends now on how the market will react. So far we believe the market is acting normally now, up and down," Qatari Oil Minister Abdullah al-Attiyah said on Monday when asked if Opec would need to cut supply soon.
Crude prices already dropped more than $1.60 on Friday in anticipation of Opec's decision and are around $3.50 below two-month highs hit last week.
Opec now appears ready to defend oil prices at a floor of about $40 a barrel for US crude, or $35 for a reference basket of cartel crudes.
Qatar's Attiyah said on Monday he saw $30-35 as a reasonable price. Opec's reference basket was last valued at $41.88.
At the group's next meeting in Isfahan, Iran on March 16 - just six weeks away - the group may yet decide to shave production to contain a seasonal second quarter stockbuild.
While the rise of China and India as consuming powers means the seasonal lull in demand following the northern hemisphere winter is now less pronounced, Opec still fears prices could fall if inventories build too quickly.
"It depends on whether demand slows but I think they will have to do something. It is unlikely we will have a second quarter this year like last year when Chinese demand exploded," said Deborah White, senior economist at SG Commodities in Paris.
Some in Opec worry the mid-March meet comes a little late for comfort to adjust supply. Middle East exports take six weeks to reach Western markets.
Opec President Sheikh Ahmad al-Fahd al-Sabah of Kuwait said that, should inventories build too quickly and prices fall, he could call a ministerial teleconference to take action.
The Middle East Economic Survey (MEES) newsletter on Monday described this as "a real prospect."
"MEES understands that any such cut would come into effect either on 1 March or 1 April; would be substantial and not a token amount," MEES said, without specifying its sources.
Opec also agreed to officially set aside their old $22-$28 range for the basket, set in March 2000, although ministers were in no hurry to formalise a new target, saying prices are too volatile.
The group was more confident that oil prices near $50 a barrel are not stifling world growth, despite lingering worries among consumer nations about inflated fuel costs.
Economists agree there is little sign yet of an energy price shock, partly because the dollar's decline on currency markets has protected non-dollar importers from the rise in oil prices, denominated in the US currency.
Oil ministers are confident another 1.5-2.0 million barrels daily of demand this year in the 83 million bpd world market, led by China, will support another year of high prices.