Oil slipped further below $59 on Tuesday and analysts said prices may continue to drift until hard evidence emerged of the extent of OPEC production cuts.

Providing some support was another forecast for below average temperatures in the U.S. Northeast, the world's biggest heating oil consumer, from November.

U.S. crude was down 31 cents at $58.50 a barrel by 0850 GMT, after falling 52 cents on Monday.

Prices hit a 2006 low of $56.55 a barrel last week and stand 25 percent below a record high traded in July.

London Brent was down 33 cents at $58.88 a barrel.

Leading oil exporter Saudi Arabia told its customers at the weekend it was cutting November supplies as part of an OPEC deal to remove 1.2 million barrels per day from oversupplied markets.

But other members, notably Venezuela and Iran, have yet to provide similar evidence. With oil prices still high by historical measures, some doubt their commitment to cut.

"Visibility is low for the time being, leaving us waiting for IEA data in early December to judge whether cuts have been enacted and leaving ample scope for speculation on OPEC cohesion," Citigroup said in a research note.

Gerard Burg, a commodities analyst at National Australia Bank, said fuel stock levels in consumer countries were key to price direction.

"Until we see the effects of the cut on stockpile levels we might not see any response... It may be a few weeks before anything happens (to stocks)," he said.

Barclays Capital technical analysts said in a research note a swift price rebound was unlikely.

"Major damage has been done to the long-term uptrend and it is unlikely oil will make a rapid recovery. Expect weakness to eventually extend towards $55 but thereafter we would be looking to reinstate a strategic long position," they said.

COLD U.S. WINTER?

Private forecaster WSI Corp. predicted below average temperatures in the U.S. Northeast from November to January. Others have made similar forecasts, pointing to higher fuel demand after a mild season last year.

U.S. weekly oil stocks data will be published on Wednesday.

Crude oil stocks, already well above seasonal norms, likely rose another 2.4 million barrels last week as refinery maintenance kept feedstock demand low, according to a preliminary Reuters poll of analysts.

Distillate stocks, which include heating oil, were seen falling by 1 million barrels and gasoline by 500,000 barrels.