The Coastguard is reminding boaties to take extra care and expect the unexpected when crossing bars to get to open water.
Two people died on Monday after their boat was swamped while attempting to cross the bar on Auckland's Manukau Harbour.
Another boat capsized yesterday crossing the Kawhia bar.
Coastguard spokesperson Georgie Smith said people needed to make sure they were well prepared.
"When crossing a bar, it's incredibly important to just take heed of the key safety messages: be really prepared; be confident; take advice from locals that know the bar really well; don't overload your boat; have your lifejackets on because it's a time of heightened risk; and really get to understand those bar conditions and know your limits."
Boaties should make use of the online resources available to learn more about crossing bars, Ms Smith said.