 On 21 January 2000, Niculae was called up to the Romania national team for the first time.On 2 February, he was in the start-up team against Latvia, counting his debut for the senior squad, at only 18 years old.Same as he did while playing for Romania U-21, Niculae marked his debut for the senior squad with a goal, netting Romania's second in a 2–0 win.