According to a government environmentalist, Dr Saad al-Numairy, the measure is aimed at reducing high levels of pollution in the southern Gulf.

Marine environmentalists, meeting at Eco Arabia 99, a two-day conference in Dubai, say recent oil spills have seriously damaged the local fragile eco systems.

Dr Numairy told the BBC that many sea captains discharge their oil tanks in the sea around the UAE.

This often takes place under cover of darkness, when it is very hard to monitor ships.

The effect is that spillages wash up on the region's beaches the next morning.

Reporting from Dubai, the BBC's Gulf correspondent Frank Gardner says with dozens of ships passing through the Gulf's narrow Strait of Hormuz each day, the region is particularly prone to tanker captains illegally sluicing out their tanks before they come into port.

Although neighbouring Oman suffers from similar problems, its penalties are less severe than those planned for the UAE.