Parrikar, who was in Panaji to accompany party's official candidate Siddharth Cuncolienkar to file nominations for the by-poll, ducked questions on the issue and remained tight-lipped.
The Minister had kicked up a storm with his allegations that some former Prime ministers had "compromised" the country's "deep assets".
Congress had demanded that he should give evidence to back his claim or tender a public apology.
Parrikar had made these remarks during an event in Mumbai while referring to the coast guard operation involving a boat coming from Pakistan. He had said he did not give details about the incident as the source might be compromised.
"After all, you have to build deep assets. Deep assets are created over 20-30 years. Sadly, there were some Prime Ministers who compromised deep assets," he had said.
Congress yesterday called the charge serious and demanded a public apology.