OTTAWA -- Even before it begins, the biggest environmental gathering since the 1992 Rio Earth Summit is facing questions whether an unfocused and contentious agenda can do anything to fight ecological decay, poverty and illness.

The 10-day World Summit on Sustainable Development, to begin on Monday in South Africa, suffered a major blow when U.S. President George W. Bush decided to skip the gathering.

More than 60,000 delegates and senior officials -- , including Prime Minister Jean Chrétien -- from more than 100 countries will attend.

But many worry about the UN-organized meeting's broad agenda, which ranges from the problems of small island states to those of sustainable cities.

It also has caused quarrels over sticky issues such as trade and foreign assistance.

"A 71-page agenda is hardly a focused conference," Environment Minister David Anderson said.

"The agenda is unwieldy," he added.

Mr. Anderson said he is disappointed but understands why Mr. Bush wants to stay away, given that the U.S. President drew the ire of environmentalists last year for rejecting the Kyoto protocol on fighting global warming.

"There was no way the President was going to attend unless it was going to be a successful conference, and you can't guarantee that," Mr. Anderson said.

"It's a conference on everything, and as a result it's not about anything," said David Runnalls, president of the Winnipeg-based International Institute for Sustainable Development.

The summit, to be held in the Johannesburg suburb of Sandton, has been dubbed "Rio plus 10" because it will take place 10 years after the UN Earth Summit in Rio de Janeiro, which put the global spotlight on environmental threats.

The South African conference aims to find ways to make economic growth more environmentally friendly and to improve the lives of the world's poorest people.

But the Johannesburg conference, which is supposed to be an attempt to put flesh on the bones of the lofty "sustainable development" commitments made at Rio, is shaping up to be a far cry from the 1992 meeting.

Rio set in motion initiatives to fight climate change and, less successfully, to protect biodiversity.

However, this year's meeting lacks a strong personality to play the shepherding role that Canadian Maurice Strong did when he was secretary-general of the Rio conference.

"Rio had a guy who knew what he was doing," Mr. Runnalls said. "Maurice knew what he wanted to get out of that conference, and he pushed like hell to get it."

UN Secretary-General Kofi Annan has tried to focus the Johannesburg agenda, calling for it to address five priority areas: water, energy, agricultural productivity, biodiversity and health.

But poorer countries are pushing other issues, including more foreign aid, more general transfers of technology and better access to trade with developed nations. Many developing countries are angry, for example, that the United States recently increased agricultural subsidies that will keep their farm exports from reaching U.S. tables.

Industrialized countries, in turn, believe they have ponied up enough aid and debt relief for developing countries.

They are looking for new partnerships that would give business, rather than governments, a lead role in overseas development and environmental protection.

Maude Barlow, chairwoman of the Council of Canadians, said industrialized countries fob off their responsibilities by promoting private-sector partnerships in development.

"There is a very clear feeling here that governments have come here to sell out," Ms. Barlow said from Johannesburg.

"Corporations are going to be handed a great deal of responsibility in areas such as water, energy and health development, and big companies . . . will be here to take advantage of this shift in attitude," Ms. Barlow said.