Queenstown Lakes District harbourmaster Marty Black said the men, believed to be from the United States, had no life jackets, no cellphones and no ''Plan B''.
Mr Black encountered the group on Sunday afternoon above the confluence of the Arrow River and ''strongly advised'' them to get off the river at that point.
''They told me they'd get out, but then I got a call from the bungy operation [AJ Hackett Kawarau Bungy] saying these guys had just floated down under the bridge at Gibbston.''
The men, understood to be staying in Queenstown, would be receiving fines of $300 for not wearing life jackets.
''Most people are being very sensible, but there are always a few who seem to think the rules don't apply to them,'' Mr Black said.
Anyone in any kind of small boat, under 6m long, including inflatables, kayaks, canoes, or paddleboards, must wear a life jacket on all rivers and lakes in the district.
Five people drowned at the weekend, including I-Ching Cheng (26), a Taiwanese national on a working holiday, who drowned at Deadman's Point in Lake Dunstan on Friday afternoon and Craig Arthur Reid (42), of Invercargill, who drowned at Ocean Beach, Bluff, on Sunday.
A 14-year-old girl nearly drowned at Brighton Beach, in Dunedin, on Sunday.
