South African President Thabo Mbeki has called on world leaders to come up with practical ideas when they meet at the World Summit on Sustainable Development in Johannesburg next week.

He was speaking at a pop concert in Johannesburg, intended to inaugurate a parallel gathering of non-governmental environmental groups.

We have seen millions of people drawn into the ranks of billions of others who are very poor

Thabo Mbeki

Denouncing failures in fighting poverty and disease since the first Earth Summit in Brazil 10 years ago, he said action rather than words was needed to bring hope to the poor of the world.

Government officials from around the world begin preparatory talks on Saturday - they hope to overcome major disagreements over key issues to be tackled at the talks.

The Johannesburg summit is expected to draw 40,000 delegates and 100 world leaders.

Security has been tightened to protect visitors from the city's notorious crime and violence, as well as protests promised by anti-globalisation activists.

Differences

"What we want now are practical programmes of action to ensure sustainable development that benefit the poor of the world," Mr Mbeki told the crowd at the Save the Planet concert.

Security has been tightened ahead of the summit

Since the Rio summit a decade ago, the South African president said, "we have seen millions of people drawn into the ranks of billions of others who are very poor.

"Indeed, since the Rio summit we have witnessed growing global inequalities as well as more migrations, epidemics, conflicts and instabilities."

This year's summit is meant to find ways to halve poverty and hunger by 2015 and to reduce damage to the environment.

However, BBC News Online's environment correspondent in Johannesburg, Alex Kirby, says the conference is already beset by low expectations and warnings that it will be little more than a talking shop.

Important differences between the participants remain - most notably a disagreement between the European Union and the US on poverty relief objectives.

US President George W Bush has already decided not to attend the summit.

And, according to the French news agency AFP, Italian Prime Minister Silvio Berlusconi has said he will wait to see what comes out of this weekend's preparatory talks before deciding whether to attend.