A newspaper in Germany has published excerpts of a confidential letter from Sir Norman to the president of the Bundestag, Wolfgang Thierse, claiming he has not been paid part of his fee.

The BBC's Mike Donkin: "A storm in an architectural tea cup"

Sir Norman was asking the president to intercede on his behalf with the government building agency, which commissioned the £400m project.

According to the report, the architect is owed almost £1.5m.

But a German official said on Tuesday that Sir Norman was being penalised for poor work.

The architect was awarded the Pritzer Architecture Prize, a top honour, for his work on the building, which features a huge glass dome with walkways.

'Services, not aesthetics'

Andre Lundt, a spokesman for the Berlin Federal Building Society, said the organisation had not paid in full because of shortcomings in his work.

Sir Norman was awarded with a top honour

"We are talking about services that were contractually agreed upon, not aesthetic consideration," he said.

The Reichstag, former home of the German parliament, reopened in April in the centre of unified Berlin.

There are reports that the complaints include a leaky glass roof, walls thin enough to hear people's conversations and not enough places to sit.

Andre Lundt spokesman for the Berlin Federal Building Corporation: "We've had a lot of negotiations with Mr Foster"

The government's move back to the Reichstag was part of the gradual shift of the German capital from Bonn to Berlin, a move envisaged since the reunification of the former West Germany and East Germany in 1990.

Since it reopened, the building has become one of Berlin's leading tourist attractions.