Senator Natasha Akpoti-Uduaghan gained entry into the National Assembly premises in Abuja after initially being denied access.
The senator, currently serving a six-month suspension imposed by the upper chamber, had pledged to resume her duties following a court ruling ordering the Senate to reinstate her.
On Tuesday, as she attempted to return, security operatives blocked her convoy, preventing it from entering the complex.
Inside a black vehicle, Senator Natasha was halted at the gate. The car ahead, which carried activist Aisha Yesufu, was also denied entry.
Undeterred, the senator stepped out of her car and walked into the National Assembly, accompanied by a group of supporters.