Oil drifted back towards $64 (€52.31) yesterday as Opec geared up to pump more crude onto a world market that is just beginning to show signs of slowing demand.

Ministers from the oil cartel will meet in Vienna on Monday against a backdrop of crude and gasoline prices that are still near record highs. Opec issued a fresh assurance yesterday that it was ready to increase its output.

"As always, Opec stands ready to supply additional oil to the market when necessary," a statement said, restating Opec's policy of "ensuring that supply is at or above demand."

The price of a barrel of crude has doubled in a two-year rally fuelled by booming demand from the world's biggest consumer, the US, and the expanding economies of China and India.

In real terms, prices have touched levels unseen since 1980, the year the Iran-Iraq war began.

Economies and industry are finally beginning to feel the strain, however, and Opec and the West's energy watchdog, the International Energy Agency, have both trimmed their forecasts for oil demand growth over the past week.

"[Increasing production] will be more of a political move on the part of Opec to calm high oil prices," said Tony Nunan, a manager at Mitsubishi in Tokyo.

Kevin Norrish, an analyst at Barclays Capital, questioned the commercial and economic logic of Opec raising output but added: "The political context and the position of market leadership would argue for Opec making a further adjustment."

US light crude was trading down 53 cents at $64.22 a barrel by lunchtime yesterday, extending a loss of 34 cents on Thursday.

London Brent crude slipped 51 cents to $63.15 a barrel.