German Chancellor Angela Merkel expressed her regret at General Motors' failure to choose a buyer for its German unit Opel, and said that a decision was urgently needed for the carmaker's future.

In an interview with German ZDF television due to be broadcast later on Sunday, Merkel said she felt there might be a conflict of interest between GM and countries with a stake in its European operations, but that progress was being made.

I regret that a final decision wasn't made, but I hope it will happen soon, because both for the workers and the economic situation at Opel, we urgently need a decision, she said.

The conflict of interest could be that we think Magna has made a very good offer ... which makes GM a minority shareholder in the whole set-up, and there may voices at GM ... who'd prefer that this minority shareholding wasn't so marked, she said.

Despite German pressure to back a bid by Magna International , General Motors Co on Friday declined to name the Canadian automotive firm as the winning bidder for Opel, leaving the fate of the carmaker up in the air.

Extending the wait on the firm's future sparked a round of angry reactions from German politicians at the weekend, who reaffirmed their support for Magna's bid.

Merkel said that more talks were necessary.

Now I hope we'll make progress next week, he said. I believe that we're still heading in the right direction.

The German government, which is facing a federal election on September 27, has offered financial backing for Magna's bid because it believes it would be the best option to save jobs at Opel, which employs around 25,000 in Germany.

Juergen Ruettgers, premier of North Rhine-Westphalia, Germany's most populous state and home to Opel's Bochum works, on Saturday urged the U.S. government to help thrash out a deal.

Sources familiar with the talks said GM directors wanted Berlin to say what financing would be available to back a rival Opel bid by Brussels-based financial investor RHJ International.

Berlin and the German states that host Opel plants have made clear they want Magna to get the carmaker and are set to provide 4.5 billion euros ($6.4 billion) in state aid to make it happen.

A source close to the talks said the next GM board meeting would be at the start of September and that two bones of contention were likely to be discussed over the next week.

One was that Berlin was insisting GM should step in if the German aid proved insufficient. The other was that GM wants to receive royalties from Opel for the use of its technology even if the German carmaker files for insolvency.

Magna remained the favored candidate, the source added.

(Writing by Dave Graham; Editing by Rupert Winchester)