Chris Brummitt, Jakarta – International aid group Oxfam has suspended some of its tsunami-relief operations in hard-hit Aceh province while it investigates suspected financial irregularities there, a spokesman said Thursday.

Relief organizations in Indonesia have pledged to carefully audit their funds amid concerns that aid dollars could be stolen by corrupt officials or contractors in the country, which is rated as one of the world's most graft ridden.

Oxfam spokesman Douglas Keatinge said investigators were probing irregularities involving "tens of thousands of dollars" at one project office covering the provincial capital Banda Aceh and surrounding districts. He gave no more details on the nature of the irregularities.

"Oxfam has taken the decision to temporarily suspend part of our operational activities in Banda Aceh and Aceh Besar while our auditors thoroughly review the issue," he said.

He said that essential services such as water trucking and rubbish collection would continue, but other activities, including house building and job creation schemes, would be put on hold in the region, which was worst hit by the Dec. 26 tsunami. Oxfam's overall budget for Aceh is $30 million.

Its early disclosure about the irregularities is unusual for an international aid organization, and highlights the pressure relief groups are under to be transparent about how funds are spent.

"Oxfam is committed to upholding the strictest and most rigorous financial controls," Keatinge said. "The temporary suspension of our operations will allow us to be more accountable to the communities that we work with, and ensure improved service delivery in the future."

The tsunami, triggered by a massive earthquake close to Indonesia's Sumatra Island, killed or left missing at least 216,000 people in 11 Indian Ocean nations, more than half of them in Aceh.

The scale of the death and destruction generated some $13 billion in aid, the most generous global response ever to a natural disaster.

Some corruption during major relief efforts is inevitable, experts say, but Indonesia has been praised for limiting graft in Aceh, chiefly by establishing a government agency to oversee the reconstruction process headed by a respected former Cabinet minister.