BERLIN (Reuters) - German Chancellor Angela Merkel said on Wednesday that Britain should be clear about what kind of relationship it wants to have with the European Union before starting talks on quitting the bloc.

"From my point of view it's completely understandable that a few days after the referendum, a few days after a new government in Great Britain is formed, that the government has to first think what are our interests, what exactly do they look like," Merkel said at a joint news conference in Berlin with visiting British Prime Minister Theresa May.

"And I think it's in all of our interests if Great Britain has a very well defined negotiating position," Merkel added.

She stressed that formal negotiations would only be possible once Britain invokes Article 50, adding that the European treaties were clear about this.

(Reporting by Noah Barkin and Paul Carrel; Writing by Michelle Martin)