British aid agency Oxfam is "confident" Sri Lanka will return $1m (£550,000) in duty paid on vehicles imported for use in tsunami relief work.
Oxfam's vehicles were kept idle in Colombo for a month
The head of Oxfam in Sri Lanka said that an "extremely fruitful" meeting had been held with the Sri Lankan finance minister on Tuesday.
Sri Lanka reimposed taxes on vehicle imports four months after the tsunami.
Nearly 31,000 people died in Sri Lanka when the tsunami struck on 26 December. Half a million were made homeless.
"The meeting was extremely fruitful and, subject to the submission of the details of the Oxfam tsunami projects, we are confident that we will have a positive outcome regarding the return of the money paid on the vehicles," said David Crawford, the head of Oxfam in Sri Lanka.
Much of the Sri Lankan coast was devastated by the tsunami
The aid agency says that the dispute over the import of the vehicles was the result of a "misunderstanding" that has now been rectified.
The money was paid by Oxfam for bringing in 25 off-road vehicles for tsunami aid work.
Sri Lanka waived duty on tsunami relief for the first four months after the disaster but warned all organisations that the tax would then be reintroduced.
The government has said it was worried that the exemption was being abused to bring in non-essential items.
"This positive move by the Sri Lankan government would allow us to reinvest that money in our programme and get help to even more Sri Lankans affected by the tsunami," Mr Crawford said.
He said that the Sri Lankan government had "made it clear" that they valued the role played by international agencies such as Oxfam, which it pledged to work "closely and positively" with in the future.
Oxfam's vehicles were kept idle in the capital, Colombo, for a month while being processed.
It says that it has helped nearly half a million people affected by the tsunami in Sri Lanka.
The aid agency works with community groups to deliver clean water, decent sanitation and better quality housing.
"Oxfam's work has expanded substantially in Sri Lanka after the tsunami hit the coastline," said Mr Crawford.
"The vehicles were essential for our work in ensuring we can reach the poorest communities over rough terrain and bad roads."