British scuba diving instructor Richard Neely and his US girlfriend Allyson Dalton sparked an all-night manhunt after becoming separated from their dive boat last May.

The couple said they spent 19 hours floating towards shark-infested waters after surfacing to find their boat had gone.

They were rescued 14 kilometres from the dive site, after a costly search operation involving seven helicopters, three planes and six boats.

Dive company OzSail were on Thursday charged with failing to ensure the health and safety of Neely and Dalton.

It has made no comment on the charge.

OzSail at the time accused Neely and Dalton of failing to follow directions or to remain in the designated dive zone, while their sale of the story to newspapers within hours of being rescued was met with media scepticism.

Some reports questioned why the pair were wearing full-length hooded wetsuits in such warm waters, and suggested they had staged their disappearance.

The case will be heard on March 23.

AFP