Trading standards officers said yesterday that in a test of 30 brands only 10 fully passed safety tests. Six brands were found to have poor-quality valves that could deflate the band rapidly, causing children to panic.
Importers of the worst bands were urged to recall them and prosecutions were being considered by officers in Greater Manchester, where the tests were carried out.
Tom Jones, chairman of the Association of Greater Manchester trading standards committee, said: 'The survey is very disturbing indeed. If they were suddenly to deflate, a child could get into difficulties very quickly.'
Among the worst five brands were three imported from China - The Wet Set, Swim, and an unbranded make - Aqua Fun, and Tommee Tippee for children aged over six months.
Jackel International, of Cramlington, Tyne and Wear - manufacturer of the Tommee Tippee brand - rejected the findings. A spokesman said the company was disappointed its bands had been singled out. He said it sold 25,000 pairs a year without complaint.
Safe makes were: Bema, Speedo, Floaties, Thomas the Tank Engine, Mothercare, Boots junior, Water Fun and Artee.