The No Excuses campaign spearheaded by Maritime New Zealand was active in Kāpiti waters on Sunday.
The nationwide campaign is aimed at making sure boaties are doing the right thing and following the rules.
"The team stopped 40 boaties and gave one skipper a warning for speeding near a dive flag," lead Maritime officer for the project Matt Wood said.
"Another skipper will receive a fine for not flying a dive flag.
"Overall, most people were wearing lifejackets, carrying communications such as VHF radios, distress beacons and more, and following the rules.