LONDON (Reuters) - Vodafone (>> Vodafone Group plc) has recruited Hannes Ametsreiter, the outgoing chief executive of Telekom Austria (>> Telekom Austria AG), to run its German business, the firm's biggest market where it is struggling in the face of fierce competition.

The world's second biggest mobile operator said on Friday that Ametsreiter would take on the German CEO job on October 1 after he unexpectedly announced this week that he was quitting his Austrian role. Shares in Telekom Austria have fallen 4 percent since the news broke.

Ametsreiter, the former marketing chief of Telekom Austria, became CEO in 2009 and steered the former state monopoly through its acquisition by Carlos Slim's America Movil (>> America Movil SAB de CV) last year. He ensured that Vienna would remain the headquarters of Slim's central and eastern European telecoms empire.

"Hannes is an experienced industry leader with an extensive background in convergence, marketing and brand," said Vodafone CEO Vittorio Colao. "We are delighted to welcome him to Vodafone."

Britain's Vodafone posted a rise in quarterly sales for the first time in nearly three years in May, but a weak performance in Germany took the shine off the results.

Vodafone is in fierce competition with Deutsche Telekom (>> Deutsche Telekom AG) in Germany where the former state monopoly is regaining market share thanks to increasing mobile data consumption by smartphone users.

Vodafone is integrating cable operator Kabel Deutschland which it bought in 2013 to help it better compete with Deutsche Telekom by selling multiple services such as fixed and mobile broadband.

(Reporting by Kate Holton; Editing by Keith Weir)