Rich from North Sea oil and with a generous welfare state, Norway has led the world ranking since it ousted Canada from top spot in 2001. The annual list ranks countries by an index combining wealth, education and life expectancy.

"The (2005) report comes out on September 7 and yes, Norway is ranked as number 1 on the human development index," UNDP administrator Kemal Dervis told a news conference in Oslo of the forthcoming report.

He gave no other details of the ranking. Last year, Norway was followed by Sweden, Australia and Canada at the top, while Sierra Leone was the last of 177 countries listed.

The news is likely to be welcomed by Prime Minister Kjell Magne Bondevik, whose centre-right government is trailing a "Red-Green" opposition alliance led by the Labor Party ahead of a Sept. 12 election.

But Dervis, on his first foreign trip since taking over as head of the UNDP this month, said the ranking was a reward for years of work by successive governments in Norway, the world's number 3 oil exporter behind Saudi Arabia and Russia.

"This is an achievement of the Norwegian people over a very long time. It cannot be interpreted as belonging to one government," he said.

Still, Bondevik has often grumbled that it is a paradox to be lagging so far in the polls when UNDP surveys have placed Norway top every year since he came to office in 2001.

The economy is set to expand by a stellar 3.75 percent this year, interest rates are at a very low 2.0 percent, annual inflation is almost non-existent at 1.1 percent and unemployment a low 3.7 percent.