LONDON (Reuters) -- Oil supplies from non-Opec producers could well fail to meet forecasts for record growth next year, relieving some of the pressure on the Opec group for an output cut to support prices, analysts said yesterday.

Widespread predictions of a surge in non-Opec supply next year were a big influence behind Opec's September decision to rein in output and head off growth in global stockpiles.

The Organization of Petroleum Exporting Countries meets again on December 4 and, despite high prices, some hawkish ministers may be tempted to push for another cut to defend the market near $30 for U.S. crude.

Ministers though should take comfort from downward revisions to forecasts for rival supply growth in 2003 that brighten their hopes of holding prices strong for a fifth year in succession.

The International Energy Agency, energy adviser to 26 industrialized nations, this month cut its forecast of non-Opec production for 2003 to 49.0 million barrels per day - up 1.0 million bpd from 2002 but some 300,000 bpd below its forecast at the start of the year.

"The key shortfall this year was in the North Sea, because of an extended run of outages, and in the United States as high natural gas prices curbed production of natural gas liquids," said David Fyfe, supply analyst at the IEA in Paris.

The IEA projects 1.45 million bpd of non-Opec supply growth next year, which would be the biggest rise on record.

Analysts say that actual supply may again fall short. Projected growth next year is led by Russia, Chad, Angola, Kazakhstan and Colombia - all producers where local instability could upset oil flows.

"Through much of the 1990s the supply growth was coming from stable places like the North Sea and the United States. This decade it's coming from places that have much less stable political situations," said Adam Sieminski of Deutsche Bank.

Steven Pfeifer of Merrill Lynch sees non-Opec supply growth of just 700,000 bpd next year, arguing that a structural shift in the global oil business means non-Opec growth has consistently been overestimated.

The rising cost of squeezing oil from mature non-Opec reservoirs has made projects more vulnerable to delay and disappointment as oil firms look to boost profits by cutting expenditure, said Pfeifer.

"Non-Opec supply growth outside the former Soviet Union will be well below expectations as the cost of finding and developing new oil reserves escalates higher, and company capital spending remains stuck at current levels," said Pfeifer.

Most forecasters still see a hump in non-Opec output growth between 2004 and 2006 as big projects in the former Soviet Union and West Africa grind on stream.

IEA figures for 2004 would mean demand for Opec oil falling next year to 25.1 million bpd versus 25.9 million this year, reason enough for the group to cut output to support prices. But Fyfe says that a repeat of this year's exceptional supply outages would mean a lower non-Opec growth forecast of "nearer one million barrels a day." "Forecasting non-Opec production ahead of time is a dark art," said John Waterlow analyst at of Wood Mackenzie, who sees more than a million bpd of non-Opec growth next year. "You can factor in developments, but you can't factor in strikes, accidents, geo-political events."

Rapid forecast growth in non-Opec Africa - including Angola's prolific deepwater sector - is particularly vulnerable to political or technological upsets.

"It all depends on how quickly oil from Angola, Chad and Sudan really flows," said Sieminski, adding that a current 2004 non-Opec growth forecast of 1.24 million bpd may prove too high.

The high cost of developing Canada's heavy oil, as well as operational hiccups at high-tech oil sands projects, has helped drag North American production below expectations this year.

Even growth in Russia, which has led non-Opec increases over the last four years, could suffer if the government continues to pursue the country's private oil giants in a legal crackdown which has already landed the head of the country's biggest oil firm Yukos in jail.