Divers are trying to repair holes in the hull and tank of the Bahamian- registered Bona Fulmar, while rescue teams pump inert gas through the tanker in a bid to prevent an explosion.
It is hoped that the 47,000-tonne tanker, whose engines were not damaged in Saturday collision, could make her way to the nearby port of Rotterdam once repairs have taken place.
A spokesman for Dover coastguard said last night: "Work is still being carried out on the tanker and she might be able to move tonight, either with the help of tugs or under her own steam. Most of the spilled petrol seems to have now evaporated."
The Bona Fulmar collided with the Mexican chemical tanker Teoatl in thick fog off the coast of Ostend, 32 miles from Dover. Around 9,000 tonnes of unleaded petrol spilled from the ruptured tanker, which was heading for the North Sea. The Teoatl was undamaged
Experts said that the fact the Bona Fulmar was carrying unleaded petrol rather than oil averted what could have been a major ecological catastrophe.