A decision is expected later today about whether Waikato Regional Council or Maritime NZ will formally investigate a boat capsizing at Tairua on Monday.

Three men, one in his 60's and two in their 40's, were rescued by emergency services after their aluminium boat capsized in heavy surf while crossing the Tairua-Pauanui bar yesterday morning.

Police and bystanders retrieving the aluminium boat which capsized while crossing the Tairua-Pauanui bar on Monday. Photo: Claire Fitzjames/Fairfax NZ

It was reported that none of the men had been wearing lifejackets at the time of the capsizing.

WRC maritime services team leader Richard Barnett says while it's understood from witnesses the boat tried to turn mid-crossing, it's still unclear exactly what happened.

He says crossing a bar is an extremely hazardous activity which is one reason why council worked with others to create a series of bar crossing videos for boaties.

'One of the big no-nos is not to be wearing a lifejacket while crossing a bar. It's a national rule that they must be worn while crossing bars.

'So it's vital that people wear lifejackets in these circumstances, make wise decisions about whether it was safe to go on the water in the first place and never try to turn mid-crossing.”

Richards says skippers of vessels who attempted crossing in such circumstances put themselves and crew at risk, as well as emergency responders who had to go to help them.

'Boaties need to make sure they do their homework and equip themselves with the knowledge and skills they need to cross bars.”

For more information on how to cross bars safely visit the Wairkato Regional Council's website at: www.waikatoregion.govt.nz/barcrossing/

Waikato Regional Council maritime services team leader Richard Barnett. Photo: File