The ruling BJP, the Congress and the AAP, which were asked by the Centre to furnish details of the sources of their overseas funding, have been given 15 days more to file their replies.
The Ministry of Home Affairs, in separate communications to the parties, had asked them to submit by May 16 details of the funding sources, including those from abroad or foreign business enterprises.
The parties have now been given 15 days more to give details of their overseas funding, a home ministry spokesman said.
The exercise was part of the routine communication sent to political parties every year to ascertain whether they violated provisions of the Foreign Contribution Regulation Act (FCRA).
Official sources said these were "not show-cause notices". If such a necessity arises, the decision would be taken only after receiving replies from the parties.
The AAP had alleged that the central government's move was a clear case of "political witch-hunt" and that it was very "dangerous" for democracy.
"It is a clear case of political witch-hunt. All the agencies at the Centre's disposal have been unleashed against the Aam Aadmi Party (AAP), its government in Delhi and its ministers, which is very dangerous for democracy," the party had said in a statement.