Leaky condoms can still be found across the city but there are fewer of them than four years ago, according to the Consumer Council's latest findings.
The council tested 10 brands, comprising 11,655 condoms, to see whether they leaked or burst under pressure and found 19 samples from two brands to be defective. This represents a failure rate of 0.16 per cent, compared with 0.19 per cent in tests carried out in 2005.
Defective condoms gave users a false sense of security and failed in their role to prevent pregnancy and the spread of sexually transmitted diseases, the council warned.
The two brands are Fuji Condom's Zero-0 Tight Fit and Moty's 003 Gold Dotted Type. Both failed international standards, which state that there should be fewer than three defective samples per 315 tested.
Moty's 003 Gold Dotted Type also failed to meet the international pressure threshold. The distributor of the Moty condom said it had contacted the manufacturer to make sure it kept a closer watch on quality and strengthened checking procedures.
The manufacturer of the Fuji condom said it had tested samples obtained from the Hong Kong distributor and no leaks had been detected. It said it doubted the council's testing methods and results.
Consumers should check the expiry date on packets of condoms and make sure there were no visible defects before using them, the watchdog recommended.
Choi Kin, former president of the Medical Association, said a condom had a 90 per cent success rate in preventing pregnancy if used correctly. A condom that leaked offered very little protection, up to 10 per cent, he said.
But there was still some risk of transmitting sexual diseases, even if the condom was used correctly, Dr Choi said.
According to Suvan Law Sui-wan, pregnant girls' services team leader at Mother's Choice, about 4 per cent of accidental pregnancies happened because of faulty condoms.
Some of the girls' partners had used defective condoms without realising and others had ripped them during intercourse. 'Sex-education lessons should stress that no method can stop pregnancy 100 per cent.'