International oil prices broke through US$67 a barrel on Friday, putting pressure on mainland refiners to stop supplying petrol, particularly the lowest-grade fuel, to consumers because they are losing money under the mainland's controlled pricing system.

In Guangzhou, where rationing was first reported, roads outside some service stations have been transformed into car parks for vehicles waiting to get their tanks filled.

Roads usually jammed by heavy traffic, such as the Airport Road and North Tianhe Road, have been clear during the past few days.

In Shenzhen, drivers have begun waiting outside the remaining 117 open service stations at daybreak, many bringing plastic containers to store extra fuel.

Lines often stretch one to two kilometres. The drivers said they had to wait three to four hours on average.

Taxis are the worst affected and can only fill their tanks at 22 designated stations. Many fear they will be forced out of business if the situation continues.

'I have to get up at 4 o'clock in the morning to line up outside the depot gate. I don't get my car refuelled until 7 o'clock or even 8,' taxi driver Huang Pengfei said.

'That leaves little time to do business. We are all exhausted by the end of the day, while our earnings are much less.'

A Shenzhen official in charge of fuel supply said the daily supply of petrol in the city is about 40,000 litres, but demand is well over 70,000 litres.

Some taxi drivers plan to petition outside the government headquarters office today.

Shanghai taxi drivers are threatening to strike on September 1 to protest against rising fuel prices despite a recent increase in subsidies paid to drivers.

In Shanghai, the so-called No 90 petrol, the lowest-quality and the cheapest, had sold out at some stations, Xinhua said on its website, without giving figures.