Issuing its first ever advice to tourists and businesses worried about the effects of the millennium bug abroad, the Foreign Office said all travellers should be aware of the possible dangers to air transport, shipping, medical services and power supplies.
Computer breakdowns in "middle ranking" nations could also hit telecommunications, financial services and water and sanitation services.
Derek Fatchett, the Foreign Office minister, also called on the International Air Transport Association to publish its secret blacklist of airports whose air traffic control systems could fail.
The IATA's pounds 13m survey of 300 airports around the globe has identified problem airports, but the association has so far refused to make the findings public because it would cause unnecessary panic.
Mr Fatchett stepped into the controversy for the first time yesterday with a plea for the IATA to publish the survey, which it has to date claimed is only for internal use.
"We would like to see them release it. We are going to try to persuade them to do so. With the public desperate to know, trying to hide the information is not going to be in anybody's interest," he said.
Mr Fatchett said that he could not yet specify which countries were behind schedule with their millennium compliance, but would consider naming individual culprits by June if they are still causing concern.
The United States and Australia are considering publishing similar blacklists this summer if the countries concerned have not improved their state of readiness and drawn up emergency plans for the event of widespread computer failure.
Mr Fatchett said that small and medium-scale British businesses operating abroad or dependent on imports should urgently prepare their own contingency plans in case the bug cripples foreign countries.
He revealed that the British embassy in Paris was contacting the Channel port authorities to ensure that shipping would not be hit by the date change, while diplomats in Cairo and Panama City were working on protecting the Suez and Panama canals for trade. Similarly, embassies throughout the EU were working with host governments to ensure that motorway tolls and other land routes would not be affected.
"The areas that give us concern are the countries of the old Soviet Union, and in South-east Asia where there has been high economic growth," said Mr Fatchett.
The UK has already contributed pounds 10m to the World Bank to help developing countries prepare for the bug, and the British Council is holding a series of seminars in key capitals across the world.
A spokesman for the IATA said that the airport authorities which had given it the information for its survey would not allow publication of the blacklist.Reuse content