Metropolitan Magistrate Babita Puniya allowed Delhi Police to quiz Kumar till July 13.
The Delhi Police had sought a five-day extension, saying the accused is required to be taken to his village in Uttar Pradesh for recovering some documents and other materials.
They also said that Kumar is required to be confronted with other co-accused Lakhpat to unearth the conspiracy.
Lakhpat was also remanded to police custody till Sunday.
Manoj Kumar, who represents Kondli constituency in east Delhi, was taken into custody in cases of alleged land grabbing and cheating.
He faces seven cases in all and an FIR in the land grab case was filed about a year back and in the assault case in May this year. (IANS)