Port authorities in most regions have applied the restrictions to prevent computer-related failures associated with the change of date to 2000 affecting cargo handling operations.

But although extra tugs may be on duty, most major shipping channels will operate as normal.

Two of the world's busiest channels, the Dover Straits in the English Channel and the Strait of Malacca between Malaysia and Singapore, will not operate any extra restrictions on top of their normal traffic separation and vessel regulation schemes. However, Turkey has said it will close the Bosphorus and Dardanelles straits to all ships over 200 metres in length for 15 hours from 1400 hrs GMT on December 31 to minimise the possible effects of the millennium bug.

Fears had been expressed that ships navigational, steering or oil pumping equipment could break down as embedded computer chips failed to recognise the date change to 2000.

Over the last 18 months most major shipping operators haveworked to adopt the provisions of an International Maritime Organisation (IMO) approved Year 2000 safety protocol.

"The shipping industry is generally well prepared with regard to equipment testing, contingency planning and expecting the unexpected," International Chamber of Shipping Secretary General Chris Horrocks said.

But there are still fears that many smaller operators may not have taken action to check for Y2K failures.

Most port operators are asking vessels to confirm they have made all the necessary checks before docking over the days just before New Year and taking extra care over the critical hours just before and after midnight.

UK Loadings suspended around midnight
Loadings of North Sea benchmark Brent crude oil at the Shetland Islands Sullom Voe terminal will be suspended for six hours from December 31 into the New Year as a precaution against the millennium bug, port sources said."There will be no loadings between 2100 GMT and 0300 GMT the next morning," an official at Sullom Voe's port control told Reuters.

At the Welsh Port of Milford Haven, all petroleum handling operations have been suspended between 2300 GMT on December 31 and 0100 on January 1 with port movements stopping an hour earlier, a spokesman said. Liquid cargo and bunker transfers will not be permitted within the hours of darkness during the New Year period at terminals within the Port of London Authority.

A spokesman at the UK Maritime and Coastguard Agency said it would be manned as though it was a busy summer's day - an unusual occurrence for midwinter. Four large standby tugs are already on station at sea - with vessels ready to deal with emergencies covering the Shetlands/Orkney area, Western Isles and Outer Hebrides, Dover Straits and Western approaches off Falmouth.

In Rotterdam a "critical period" will operate from 1000 hours local time (0900 GMT) on December 31 until 1400 hours on January 1 with restrictions on movements and docking already in place. At Marseilles, in France, an emergency team will be on duty and a total vessel movement stoppage will be enfored for two hours before and after midnight. Norway's Statoil has said it would also suspend offshore crude loadings for a few hours before and after midnight No tankers will be connected to loading buoys during that time. Reuters In Singapore the critical period will operate from 1800 hours local time on December 31 to 2200 hours on January 1.