UNITED NATIONS, Jan 5: As the world leaders gather in Indonesia to launch an emergency appeal for the countries devastated by the Asian tsunami , the top UN relief co-ordinator said on Wednesday that the emergency operation was making speedy progress but also faced extraordinary problems.

"We are making extraordinary progress in reaching the majority of the people affected in the majority of the areas", Emergency Relief Coordinator Jan Egeland told a news briefing on day 10 of the disaster that killed more than 150,000 people - with the number still rising - injured 500,000 more and left up to 5 million lacking basic services.

"We are also experiencing extraordinary obstacles in many, many areas and nowhere do we have bigger problems again than in northern Sumatra and the Aceh region," he added.

"We still have logistical bottlenecks although that's part of the extraordinary progress that we have been solving many more of the bottlenecks earlier than we've done in similar disasters before."

Warning that diseases were worsening by the day in areas that the massive relief operation was not reaching, Mr. Egeland said the top priority "on his wish list" were C-17 transport planes to fly in heavy earth moving equipment to increase the capacity of the airport in Banda Aceh, which registered the worst devastation by the tsunami.