Plans for a north Europe high-speed train network linking Eurotunnel to Britain and the continent must now be considered irreversible, French Transport Minister Jacques Douffiagues said.

Transport ministers and officials from Belgium, France, West Germany, Great Britain and the Netherlands met in Paris recently to discuss progress in the project to connect major cities in the five countries.Plans are to bring an integrated rail system between London; Paris; Brussels, Belgium; Cologne, West Germany; and Amsterdam, the Netherlands into service in 1993, when Eurotunnel opens. West Germany has agreed to extend the line to Frankfurt by 1993.

At a side meeting, the ministers said they may build a high-speed rail link between eastern France and southwestern Germany. Mr. Douffiagues said the route now accounts for about 20 percent of French domestic rail traffic. He added that the volume could double by the year 2000.

He also said the ministers welcomed the study being carried out by Britain on increasing rail capacity between London and the tunnel entrance.

The study is due to be presented to the British government in early June, he said. Britain has said it did not intend to upgrade its conventional rail line between London and the coast.

The French proposal for a maximum load of 17 tons an axle was accepted by the other ministers, and orders for equipment should be placed at the end of the year, Mr. Douffiagues added.

The ministers will meet again in June to discuss final project reports

from the five rail companies on financing and other details. Specifications for the scheme have been decided, but the sharing of the work has not.