A meeting of ministers from oil-producing countries to discuss crude output began Thursday in Vienna with hopes of a consensus but concerns over the price of oil.
Going into the meeting of the Organization of Petroleum Exporting Countries, the oil ministers of Angola, Libya, Iran and Ecuador said they were hopeful of reaching an agreement, unlike in June 2011 when the meeting broke up amid divisions over output.
"For sure they will not have any problem," Iranian Oil Minister Rostam Qasemi replied, when asked if members of the cartel that supplies a third of the world's crude were happy with the production ceiling.
Nigerian Petroleum Minister Diezani Allison-Madueke was nevertheless cautious.
"I am sincerely hoping that that (a lack of consensus) does not happen. I do hope that that is not the case today."
Ecuadorian Natural Resources Minister Wilson Pastor also warned that would send "a bad signal to the markets."
OPEC members have been divided over how to respond to plunging prices and uncertainties over global energy demand, with kingpin Saudi Arabia recently ramping up production while hawks Venezuela and Iran have called for cuts so as to boost prices.
On Thursday, most members agreed on an average price of at least $100 per barrel, with Angolan Oil Minister Jose Botelho de Vasconcelos describing this as "the comfortable level."
"I think $100 would be good for the global economy, the main point is to stabilise the price at this level," added his Libyan counterpart Abdel Rahman bin Yezza, hoping for a swift resolution of the eurozone debt crisis.
The price of Brent crude oil has tumbled from $128 a barrel in early March to $96, mainly on expectations of weaker demand caused by the euro's troubles and amid a slowing Chinese economy.
Qasemi however aimed higher, citing a "logical price... between $100 and $120."
Disagreements also exist between OPEC members over the amount of crude needed on the market.
"I think the market is oversupplied now, the supply is over demand," Bin Yezza told journalists, putting the excess supply at "maybe 1.8 million or 2.0 million."
Iran, which faces a looming oil embargo by the European Union, called for members to "comply with the ceiling" of 30 million barrels per day (mbpd) set in December.
OPEC's 12 nation members are collectively pumping out more than this ceiling, with estimates ranging from between one and three mbpd extra, helping to push down oil prices.
In the first quarter, Saudi output jumped 250,000 barrels per day to 9.9 mbpd from a year earlier, according to OPEC estimates, in anticipation of sanctions on the organisation's second biggest oil producer Iran.
Secretary-General Abdullah El-Badri meanwhile said in Vienna this week that he was "sure" members would reach a consensus.
OPEC ministers are also expected to discuss a replacement for the Libyan El-Badri, who is set to retire at the end of the year.
So far, four candidates for the position have emerged, from Ecuador, Iran, Iraq and Saudi Arabia.