A US firm researching the logistics industry says the operations of many commercial vessels in the Red Sea have been affected as Yemen's anti-government Houthi group continues to attack ships in the area.

Project44 says that, as of Tuesday, the operations of 185 commercial vessels had been impacted. It estimates that 157 of them are rerouting around the Cape of Good Hope in South Africa.

The firm says the majority of the rerouted ships will experience a seven- to 20-day increase in transit time. It adds that transport costs are also climbing, as some rerouted vessels have increased their speed.

The United States has established a multinational initiative to ensure safe passage through the area.

The US Central Command says its forces shot down 12 drones, three ballistic missiles and two cruise missiles in the southern Red Sea that were fired by the Houthis over a 10-hour period from early Tuesday morning.

But analysts say global logistics could suffer if shipping is further disrupted.