The National Asset Management Agency is demanding tax returns from some developers in an effort to ensure they are disclosing the full extent of their assets to the agency.

NAMA has threatened enforcement proceedings where developers are being uncooperative and the agency believes they are hiding the full extent of their properties and other assets.

When developers submit business plans to NAMA, they are obliged to inform the agency of their assets and are frequently asked to provide tax returns.

By matching the tax paid on rental income to the list of properties, the agency can see if the developers have been honest and declared all their assets to NAMA.

However, it is understood that some developers have refused to submit tax returns.

A spokesman for NAMA said failure to give information can prompt a credit check to see if there are undisclosed assets.

If NAMA finds that a developer is being uncooperative it can take enforcement proceedings against the borrower.