Security forces are controlling who enters the main office of the crisis-hit Nigerian Football Federation in the capital Abjua, BBC Sport has learned.
Soldiers and riot police are manning the entrance of the building.
It follows last week's court ruling that NFF president Amaju Pinnick lost his post to Chris Giwa in elections in September 2014.
Giwa and his team had said they would occupy and take over the NFF offices to start work on Monday.
The NFF has appealed against the court ruling, insisting that Pinnick is still the head of the federation.
And staff of the Fifa-recognised NFF, including the general secretary Mohammed Sanusi, are currently working in the building.
Giwa's faction and all other non-NFF staff have been denied access into the football house by police, who have been in attendance since Sunday.
"We got here this morning and the police requested our identity cards, then we were let into our offices," an NFF staff member told BBC Sport.
"Only those without any proof of NFF identifications are prevented from coming to the building."
The ongoing power struggle means Nigeria face the prospect of a Fifa ban, which could put their World Cup qualification hopes in jeopardy.