JAKARTA (Reuters) - Tech-savvy Indonesians are using social network Twitter to beat a slow government in delivering relief to disaster victims, after a tsunami and volcanic eruptions stretched official aid capacity in the sprawling archipelago.

The Southeast Asian country of 17,000 islands, where transport can be difficult at the best of times, was hit by a tsunami, earthquakes, floods and volcanic eruptions within the space of a few weeks last month, and the death toll keeps rising.

Organizing effective aid management has proved challenging for authorities in remote regions or where infrastructure has been destroyed by giant waves or scorching ash clouds.

But when a community-based group near the erupting Mount Merapi volcano, which has killed over 300 people, sent a message, or tweet, on Twitter that food was piling up in the next town and there were no vehicles to pick it up, over a dozen cars lined up to deliver it within 10 minutes.

“It was so fast I almost didn’t believe it,” said Akhmad Nasir of Jalin Merapi, an information network built by local communities living on the slopes of Mount Merapi on Java island.

Started as a radio community in 2006 to monitor Mount Merapi’s activity, Jalin Merapi has helped shelters that are unable to receive government aid by deploying about 700 volunteers who report by tweeting specific aid needs.

The number of Indonesians using Twitter is multiplying every year. Twenty-one percent of the country’s Internet users visited the site in a June survey by digital market research firm comScore, the highest proportion in the world compared with 12 percent for the United States.

The country, where 45 percent of the 240 million population is under 25, is also the third biggest user of social networking site Facebook.

Sutopo Purwo Nugroho, director of disaster risk reduction at the National Disaster Mitigation Agency, said the government had established communication systems for volunteers and soldiers but it could not cover all of the 700 refugee centers scattered around the foot of Mount Merapi.

“Little shelters often cause problems in aid distribution. To equally divide aid to 700 different shelters is difficult, almost impossible,” he told Reuters.

The shelters have harbored over 200,000 refugees since the volcano began spewing ash and lava in late October.

Jalin Merapi’s Twitter account saw more than 12,000 tweets this month alone, linking 33,500 followers.

“Info please, which shelters need baby clothing and porridge, blankets, we are on the way,” said one such tweet by follower @dkurniawan.

Jalin Merapi’s Nasir said the most unforgettable moment was when the community announced they needed help to provide meals for 30,000 people, and the meal was ready in four hours.

“I think what we experience now shows that solidarity in a time of crisis does exist,” Nasir said.