BERLIN, August 8, 2008 (AFP) - The German government's top human rights official said Friday he has been prevented from meeting dissidents on a visit to China because of a crackdown by authorities for the Olympic Games.

'I have been in Beijing since Tuesday morning and it has not been possible to travel to other provinces. None of the interviews (planned) have taken place because of fear about meeting me,' Guenter Nooke said.

'This is because controls have tightened in the run-up to the Olypics. Lots of people have had to leave Beijing, and human rights activists and dissidents have been put under house arrest,' told German broadcaster SWR from China.

'There are many indications suggesting that the Chinese government is doing all it can to silence any kind of protest.'

The Games, which run through until August 24, are being seen in many countries as an opportunity to pressure China into human rights concessions, notably with regard to Tibet.

Neither German Chancellor Angela Merkel, President Horst Koehler nor Foreign Minister Angela Merkel were present in China for Friday's opening ceremony.

The highest German political representative in China will be Interior Minister Wolfgang Schaeuble, who is also sports minister, but he was not due to arrive until the Games' second week.

Merkel caused a spat in relations between Germany and China last September when she met with the Dalai Lama.