The United Nations emergency relief coordinator, Jan Egeland, has said reconstruction in the Indonesian province of Aceh is moving too slowly.
Egeland said survivors living in tents were understandably frustrated
Mr Egeland said better leadership and coordination were needed in the region, where much of the infrastructure was wiped out by last year's tsunami.
Mr Egeland noted that aid organisations had "quite a lot of money" to use.
But many of them, both national and international, had miscalculated the longer term needs, he said.
Tens of thousands of people there were still living in rubble-strewn refugee camps, and the situation is made worse by the rainy season which started this month.
"We did well in the emergency phase, but the reconstruction went slower than we hoped," he told reporters on a trip to Aceh.
"It's clear that we must move much quicker now to put people away from the tents and into permanent houses.
All agencies and all NGOs need to work more together."
In the aftermath of the tsunami that killed 232,000 people - 170,000 of which in Aceh alone, the global community pledged more than $4bn in aid to Indonesia.
Last month, the UN published a plan calling for the construction of 15,000 pre-fabricated homes over the next six months.
The Indonesian government agency overseeing reconstruction says it is building another 20,000 homes and it hoped to build many more.