Now they are slender and lightweight.

Roads and Maritime Services (RMS) have launched a campaign to encourage boaters to suit up at the start of the day.

"A lifejacket never ruined a day on the water - that's the message this campaign gets across," RMS South Coast acting regional manager Rod McDonagh said.

"They can be worn all day without stopping you from having fun, whether you're fishing from a tinny, towing your mates while they waterski or out for a day on the water with the kids."

Mr McDonagh said the only way to protect against the unexpected was to wear a lifejacket.

"A lot of people think that because they're good swimmers or experienced on the water that they're invincible, but obviously if you hit your head or have a heart attack your chances are minimised," he said.

"No-one expects to fall in the water and get separated from their vessel."

In the 10 years to June, 93 per cent of the 167 people who died on NSW waterways were not wearing a lifejacket.

"It's no good just having lifejackets stowed away on board," he said.

"A lifejacket can only save your life if you're wearing it, that's what this campaign is all about."

Boating safety officers conducting random inspections of recreational vessels over the Christmas period will give away tickets to the New Year's Test cricket and the one-day series matches at the SCG, as well as NSW SpeedBlitz Blues cricket matches, to everyone on board if they are all wearing lifejackets.