BRUSSELS, Belgium -- The European Union becomes 15-strong on New Year's Day, embracing Austria, Finland and Sweden and becoming a bigger and richer match for its trading partners.


As midnight tolls the Union will spread its wings northwards along Finland's eastern border -- giving it a frontier for the first time with Russia -- and eastward to Austria, bringing the Union to the edge of the former Yugoslavia. With the enlargement -- the EU's first since 1986 -- the bloc's territory will expand by one third, its population by 6.2 percent and its total gross domestic product by 7 percent, confirming its role as the world's largest trading bloc.


Although the United States will continue to outstrip the Union's 3.2 million square kilometers for sheer size, it will be only three times rather than four times bigger.


Japan will be even more dwarfed than it is at the moment. It is less than 12 percent the size of the enlarged bloc which now extends from the Arctic to the Mediterranean.


The EU's population will expand to 370 million from 348 million, 40 percent more people than there are in the United States and 64 percent more than in Japan.


The three highly industrialized new entrants, whose populations enjoy a high standard of living, will add to the Union's competitiveness on the world trading stage and open new possibilities for exports, officials said.


With their entry, the EU's total gross domestic product will rise by 7 percent, making it 10 percent greater than the United States and 64 percent more than Japan.


GDP per head will rise by about 1 percent. Austria at 122 percent and Sweden at 114 percent are well above the EU average while Finland, at 88 percent, is below.


But existing EU members Luxembourg at 168 percent, Denmark at 140 percent and Germany, 126 percent, will still be the richest EU members.


Sweden will be the Union's third largest country in geographical terms, after France and Spain, while Finland will be the fifth largest.


In popular referendums Austria's people voted by 66 percent, Finns by 56.9 percent and Swedes by 52.3 percent to join the Union.


Voters in neighboring Norway voted against joining the enlargement train. But Norway, along with Iceland, will continue to have close trading links with the Union through the European Economic Area common market, which has linked the EU and the European Free Trade Association in a single trading zone since Jan. 1, 1994.