Banks were earlier asked to submit details by August 31, but a majority of banks are still collecting information.
De Silva said banks have asked for an extension and was awaiting a response from the authorities.
The Central Bank of Sri Lanka ordered banks to report details of accounts and other assets that have lain dormant for more than 10 years, as the first step in taking them over.
It is estimated that about 30 billion rupees may be in dormant accounts. The central bank says the taking over of dormant accounts does not mean that the money has been permanently seized by the government.
Owners of assets could reclaim them from the central bank after proving their identity.
Those who show up, will be repaid according to their credit balances in the special account, together with accumulated interest, the Central Bank said without spec