The August level compares with around 35,000 tpd that the refiner had run on average in July. It was the lowest throughput level seen for Shell Singapore since September, when it ran at just 49 per cent of capacity or 29,000 tpd.

Refiners in Singapore said that their basic refining margins have been in the red in the past month, with losses estimated at around 50 cents per barrel.

Complex margins were more varied, depending on the refinery configuration, but some refiners said they saw complex margins at around 20 cents per barrel in the negative.

"If you look at today, margins are better because crude prices have fallen sharply, but overall in the past month, crude has been expensive relative to products," said a refiner in Singapore. Other refiners were also running at levels below capacity.

Industry sources said that Esso Singapore was likely running its 2,20,000 barrels per day refinery (bpd) in Singapore at around half its capacity, although this could not be confirmed as officials at the company declined to comment on run rates.

Mobil Singapore said last month it had cut July runs at its Jurong refinery to 200,000 bpd, or 66 percent of capacity. Sources said the cuts would likely be maintained in August. Mobil's Singapore refinery has a capacity of 300,000 bpd.

Singapore Petroleum Refining (SRC) had already said early last month that it would run its 285,000 bpd Merlimau refinery at 200,000 bpd in August, due to poor refining margins caused by overcapacity and poor Asian demand for products. For July, SRC ran an average of 250,000 bpd.

"The market hasn't changed very much from the beginning of the year, it's bad, it continues to be bad," said a trader with a major oil company.

Crude prices have risen in recent weeks, as a global supply glut was reduced after an agreement by the Organisation of Petroleum Exporting Countries (OPEC) to cut production.

Last week, benchmark Brent crude futures trading in London reached briefly a 20-month high level, on market confidence the producers' output cuts would be maintained. But products prices in Asia have lagged the crude price rise.

Analysts have said poor refining margins in Asia were due more to an increase in capacity than weak demand.

Mark Flannery of Credit Suisse First Boston said in a report last month that Asia's oil demand was expected to grow by 500,000 bpd this year, up 2.6 percent from 1998. But with new refining capacity coming up in Taiwan and India, the rise in demand this year would have limited impact in lifting refiners' margins.

Flannery forecast that complex margins in Singapore this year and next year would average around $1.00 per barrel, compared with his earlier forecast of $1.60 and $1.90, respectively.