Beijing: China kicked off the last leg of its Olympic torch relay on Friday under hazy skies and with a threat of rain complicating plans for the opening ceremony.

The relay is scheduled to end around midday at a school hosting an Olympic Youth Camp, with 140 torchbearers lined up to take part in the culmination of a national relay.

Beijing has spent heavily to curb pollution, but the air quality for the start of the Games is expected to be only just within the guidelines for safe levels.

There was also a chance of rain for the evening, despite research into weather manipulation that some had thought would allow Beijing to ward off rainfall.

"Whatever happens the opening ceremony will continue...We have contingency plans for temporary showers, rain and drizzle," said Wang Wei of the Olympics organising committee.