The Government has confirmed its withholding over €10m in funding from aid agency Goal.
The US Agency for International Development launched an investigation in April into "alleged irregularities" relating to aid programmes in Syria.
In a statement, the Department of Foreign Affairs & Trade said that it remains seriously concerned about the issues under investigation
It says the Department took the decision to withhold funding which had been allocated for Goal's development and humanitarian work in 2016.
The total amount of Irish Aid funds currently on hold is €10.1m - some €7.16 million of that in long-term development funding.
Goal says it is doing its best to maintain operations despite the funding being withheld.
The charity has also commissioned a report into the matter, which has been passed onto the Department.