Temasek, the sovereign wealth fund, and Germany’s Tui are in talks to merge their shipping operations in a deal that could see the Singaporean group take a stake of more than 20 per cent in the Hanover-based travel group.

A merger of Tui’s Hapag-Lloyd unit and Neptune Orient Lines, 68 per cent owned by Temasek, would create a global force in container shipping to rival the likes of Denmark’s Maersk Line.

People close to the discussions said one option would see Temasek put its 68 per cent stake in NOL into Hapag-Lloyd and take a share of Tui. Given current valuations, Singapore could end up with an estimated 23 per cent of the enlarged group. Combining Hapag-Lloyd and NOL would bring together the US and African routes of the German group with the Asian routes of its Singaporean rival.

A deal would mark Temasek’s latest incursion abroad. Last month, it increased its stake in UK bank Standard Chartered to 19 per cent. In December it became the lead investor in a recapitalisation of troubled Wall Street bank Merrill Lynch, injecting $4.4bn for a 9 per cent stake.

For Tui, pooling shipping assets with Temasek would confirm a change of strategy that had once envisaged a divestment of Hapag-Lloyd. It may also take pressure off Tui chief executive Michael Frenzel, who has been criticised by investors about the poor returns of his strategy, designed to balance the tourism and shipping business cycles.

People close to the talks said reaching a global scale in shipping as a complement to tourism would allow Tui’s shareholders to decide whether to split the operations or stick with the current strategy.

Mr Frenzel is said to favour putting NOL’s president and chief executive, Thomas Held, a German, in charge of the merged container-shipping service.

People familiar with contacts between Tui and Temasek regarding Hapag-Lloyd-NOL stressed that talks were at an early stage.

A spokesman for Tui said “negotiations are not taking place”, repeating the line adopted when reports first surfaced last month. However, people close to the situation insisted that “early-stage talks” had been going on for several weeks. They said important hurdles might well be overcome by next month.

NOL said it would not “comment on rumours”. Temasek declined to comment.