People heading out on the water in Northland over the busy summer season are urged to wear lifejackets, keep their speed down and fly a dive flag if they have divers in the water.
Chidambaram Surendran, the Northland Regional Council's Deputy Harbourmaster, says the holiday period is a busy one around the Northland coast.
"While some years can be worse than others, failure to use dive flags, or not using them properly, is a common problem. Last year was especially bad, so we'll be keeping a close eye on this issue over summer, including issuing $200 infringement notices if necessary," Mr Surendran said.
"It's absolutely vital for everyone's safety that it's clearly signalled whenever divers are in the water."
A blue and white dive flag must be clearly visible from 200 metres away. A lifejacket must be carried for every person on board.
For tips on how to stay safe: www.nrc.govt.nz/safeboating.