The OPEC deal to curtail global oil production has become shrouded in doubt after the cartel's second-largest oil producing nation posted record high export figures in December.
Oil prices slumped by 4 percent on Monday as Iraq's southern Basra ports reached a record high of 3.51 million barrels per day (b/d) in December, according to the oil ministry.
"The sad thing is that history suggests (OPEC countries) do not tend to stick to this kind of deal… I mean it is probably in their interest to but investors could well be disappointed," James Butterfill, head of research at ETF Securities told CNBC in a phone interview on Tuesday.
OPEC ministers agreed in November to cut oil production from 33.8 million b/d to 32.5 million b/d in an effort to prop up prices and curb global oversupply.
Iraq's oil ministry stressed Monday that its regionally high levels of oil exports would not impact its commitment to comply with OPEC's production cut. However, investors were concerned that the ports based in the north of Iraq would be able to outweigh the record high export figures from the south.
"We could expect 80 to 90 percent compliance (from OPEC and non-OPEC countries) by the time we get through to Q2 and then the question of course is whether that is going to continue into the second half of the year," Michael Cohen, head of energy commodities research at Barclays told CNBC on Tuesday.
"It is one of the reasons why we see (oil) prices higher in the first half and lower in the second half because I think what is likely to happen is that many of these OPEC countries will start to see the fruits of this compliance (deal) and they see the higher prices and they start to put their feet back on the pedal again," he added.
Brent crude traded at around $55.01 a barrel in early afternoon trade on Tuesday, up 0.13 percent, while U.S. crude was around $52.04 a barrel, up 0.17 percent.