MENTAWAI ISLANDS (Indonesia) - COSTLY warning systems installed across Asia since the deadly 2004 tsunami did nothing to save villagers on these remote Indonesian islands who saw homes and loved ones swept away by a giant wave this week.

Such systems can be effective for people living hours away from where a tsunami is forged but are often unable to help those most at risk. A 3m wave struck the Mentawai islands on Monday just minutes after a massive earthquake offshore, killing more than 400 and destroying hundreds of homes in 20 villages.

There are questions about whether Indonesia's system was working properly, but even if it was, a tsunami generated by an earthquake so close to shore can reach land long before there's a chance to raise an effective warning, experts say.

Mr Piatoro, a coconut farmer on the wave-battered island of Pagai Selatan, said he and his family ran toward higher ground when the water slammed into their home, but it was too late. The water snatched his feet from under him, and he was sucked under the waves, tumbling over and over. His wife was torn from him.

'I felt like I was boneless,' Mr Piatoro, 49, said on Friday as he sat alone on a hospital mat, skin scraped from his calf and stitches on a foot wound. Like many Indonesians, he has only one name. It was not clear if his wife had survived.

Tsunami alerts were sounded by scientists within minutes of the earthquake, but some villages have no telephone lines, making it extremely difficult for a warning to get through in time.

Warning systems don't help