A Wellington man is confident he can break the world record for swimming underwater on a single breath, after setting a New Zealand record in the event.
David Mullins swam 257 metres under water in 4 minutes 18 seconds, completing the equivalent of more than five laps of an Olympic sized swimming pool in Porirua.
Mr Mullins was using a fin, but no breathing apparatus during the swim on Friday.
His distance surpassed the world record of 255 metres held by Frederic Sessa of France, but remains an unofficial record as the swim was not carried out in front of international judges.
Mr Mullins says when he completed his swim he still had some energy in reserve, so he's sure he can extend the world record by up to 20 metres in front of judges in two months' time.