The court also asked whether any rent was being paid by the party for its use.
During the arguments, Advocate General Shrihari Aney stated that the government's stand was clear that if any construction or extension is not allowed under the law, the civic body must demolish it.
No building plan regarding the plot "to justify the structures" was available, he conceded, and said "anything not permissible under the law must go".
"Anything wrongly built will be demolished," he said.
According to the Nariman Point Churchgate Citizens Welfare Trust, the petitioner organisation, there were illegal alterations at the BJP office, and while the civic body had permitted construction of 2,682 sq ft, the existing building, with as many as 14 chambers, has over 9,000 sq ft area.
The petitioner's lawyer also said that there was no sanctioned plan of the building, which was supposed to be a temporary structure but has been turned into a permanent one.
A division bench headed by Justice Abhay Oka asked if the party was ready to "bring it down" to 2,682 sq ft.
The lawyer said he would seek instructions.
The bench adjourned the hearing till tomorrow after directing the government to produce agreements regarding the land, and inform if any rent was being paid by the party.
