COPENHAGEN (Reuters) - Maersk and Hapag-Lloyd ( HLAGF ) could add more container vessels to an alliance announced earlier this year if shipping disruptions in the Red Sea continue, the companies said on Tuesday.

Attacks in the Red Sea by Iran-aligned Houthi militants have since late last year forced shipping companies to reroute traffic away from the Suez Canal and instead sail around Africa, a longer journey that ties up more capacity.

Maersk and Hapag-Lloyd ( HLAGF ) in January said they had agreed on a new collaboration, starting in February of 2025, to transport a combined 3.4 million containers annually with a fleet of 290 vessels, in a tie-up known as the Gemini Cooperation.

But the two shipping giants on Tuesday said that the collaboration could grow to 340 vessels and transport a combined 3.7 million containers if the disruptions in the Red Sea continue.

Joining forces will allow Hapag-Lloyd ( HLAGF ) and Maersk to offer more frequent and flexible services, making their operations more efficient and reliable, they said.

The companies will announce in October this year whether they expect to implement their original plan, which relies on the Red Sea and Suez, or instead adopt the alternative plan of sailing around Africa with a larger fleet, Maersk said.

Hapag-Lloyd ( HLAGF ) and Maersk have set an ambitious target of delivering schedule reliability of above 90% once the network is fully phased in, with Denmark's Maersk providing 60% of the vessels and Germany's Hapag-Lloyd ( HLAGF ) 40%, they said in January.