By Tom Käckenhoff

DUESSELDORF Thyssenkrupp should explore a sale of its warship division to peers, in addition to private equity players and a potential stock market listing, according to influential German labour union IG Metall.

Leaders should "keep an eye on industrial investors", IG Metall said in a union handout seen by Reuters, adding that while the union remained open for a full or partial sale of the business, options should also include keeping the division.

Thyssenkrupp is currently exploring options for Thyssenkrupp Marine Systems (TKMS), which builds submarines and frigates, with scenarios ranging from a possible spin-off to a joint venture with a rival.

IG Metall, Germany's biggest and most powerful labour union, said last month that it would set up a committee to join the sales talks, and a first meeting with TKMS leadership is scheduled for June 22, the handout said.

Sources told Reuters that possible industrial partners for TKMS are Dutch group Damen and Sweden's Saab, while private equity players, including Carlyle, are also interested.

Outlining demands such as job and site protection, IG Metall said there should be no break-up of TKMS in any sale, adding any divestment could only happen with the consent of labour representatives.

(Reporting by Tom Kaeckenhoff; Writing by Christoph Steitz; Editing by Miranda Murray)