OLD and potentially dangerous lifejackets have been traded in for new slimline versions as part of a program encouraging boaties to practice better water safety.

The State Government's Old4New program has so far seen boaties trade in their old lifejackets for 26,000 of the new, modern and safer lifejackets.

The Centre for Maritime Safety iniative encourages people to trade in their old-style block lifejackets in exchange for signficiant discounts on the latest slimeline models.

Tweed MP Geoff Provest said many of the traded in lifejackets were unusable to the point of being dangerous, with some containing waterlogged filling.

"These lifejackets were common decades ago but some of those handed in under the Old4New program would be lethal in an emergency situation," he said.

Mr Provest said the number of boaties wearing lifejackets had increased from nine per cent ten years ago to more than 45 per cent today.

He said the campaign van had visited more than 650 sites across NSW in the past five years, encouraging use of lightweight modern lifejackets.

"The van sold the latest lightweight models at a subsidised price and buyers could get further discounts if they exchanged their old lifejackets,” Mr Provest said.

"The Old4New team has travelled 126,000 kilometres and has collected more than 24,000 old-style lifejackets since 2013, selling more than 26,000 of the latest models.

Similar schemes have now been adopted in New Zealand and other Australian states and is expected to start again next April.