FRANKFURT, Sept 29 (Reuters) - The German stock exchange operator Deutsche Boerse has begun the search for a new chief executive that includes both external as well as internal candidates, the company's chairman told Reuters on Friday.

Deutsche Boerse CEO Theodor Weimer said in June that he would not pursue another term when his contract runs out next year at the helm of one of Germany's most valuable companies, saying "fresh blood" was needed.

"We have set up a process that follows the principles of good governance. This process is proceeding in an orderly manner and as planned," Chairman Martin Jetter said in response to a question about the status of the search.

Weimer joined the German exchange operator in 2018, becoming one of the country's highest-paid corporate chiefs and ushering in a period of relative calm after turbulent years.

Jetter said the search process "includes talks with internal and external candidates, who must possess all the necessary qualifications and experience for this challenging position".

Deutsche Boerse has mandated the headhunter Heads! International to help conduct the search, a person with knowledge of the matter said.

Heads! didn't immediately respond to a request for comment. (Reporting by Tom Sims; Editing by Elisa Martinuzzi and Rachel More)