Oil prices slipped in Asian trading Thursday amid fresh concerns of weakening global growth which would dampen energy demand, dealers said.

The firmer greenback, which makes dollar-denominated commodities like crude more expensive for foreign buyers, was also a factor behind the weaker oil prices, they said.

In morning trade, New York's main contract, light sweet crude for July delivery dropped 56 cents to $121.74 a barrel from $122.30 at the close of floor trading in the United States on Wednesday.

New York oil prices had shed $2.01 Wednesday. London's Brent North Sea crude for July delivery fell 45 cents to $121.65 a barrel.

The OECD slashed its growth forecast for the world's industrial powers on Wednesday, raising fresh worries that energy demand would weaken, dealers said.

"It is very clear that the OECD countries are going to see soft demand," said Jason Feer, vice president of energy market analysis at Argus Media Ltd.

"All that is very bearish in terms of energy demand," he said.

The Organisation for Economic Growth and Development in a twice-yearly survey said its 30 member economies were confronting "three adverse shocks" - financial market uncertainty, a housing downturn and soaring food and energy prices.

The Paris-based think tank predicted that momentum in the industrialised world would slow to 1.8 per cent this year, from 2.7 per cent in 2007, and 1.7 per cent in 2009.