Queenstown Lakes harbourmaster Marty Black is troubled by the number of people boating this summer without life jackets and in cheap inflatable boats.
"There are still numbers of people who are quite naughty," he said.
He had general concerns about people not wearing lifejackets while paddling cheap inflatable boats in deep water.
The inflatable boats cost about $300 and were being used by overseas visitors, he said.
"Most we have caught have been European visitors, picked up without life jackets on . . . We've had silly buggers, up the lake, a front coming on, no life jackets," he said.
At least six life jacket fines had been issued to people on Lakes Wakatipu and Wanaka in the last 10 days or so, he said.
Another concern was that people were speeding too close to dive flags. Problems had been reported by divers working on weed control, Mr Black said.
