Kobe, Japan – Political constraints in Indonesia are discouraging international non-governmental organizations from assisting victims of Asia's tsunamis, activists at a global conference on disasters said on Saturday.

"We are considering working in Sri Lanka... but it is very difficult to do so in Indonesia," said Masakiyo Murai, director of Citizens Toward Overseas Disaster Emergency.

A number of international humanitarian groups have been operating in Indonesia after the killer tsunami, but Jakarta has said that foreign aid workers and journalists in worst-hit Aceh province must register and be accompanied by the military if they travel outside the main towns.

"Political interference is a big concern," said Murai, whose group has sent members to more than 30 countries hit by national disasters including Turkey, Taiwan and Papua New Guinea.

The group based in Kobe, formed shortly after the Japanese city was hit by a killer earthquake in 1995, aims to improve disaster victims' self-reliance through means such as building job security.

"We have to provide support equally for victims because it's a natural disaster, but we cannot provide support that only benefits the government and ruling parties," Murai said.

Murai said more foreign aid workers would be deployed to Indonesia if the government were more welcoming to non-governmental humanitarian groups.

The move by Jakarta has been seen as an attempt by the government to reassert its authority over Aceh, which had previously been closed to most foreigners as the military pursued a crackdown against separatist rebels.

Some 4,500 delegates from 150 nations are gathered in Kobe for a United Nations-sponsored conference on disaster reduction in the wake of the tsunami catastrophe, which killed some 220,000.