 Since he was still eligible to play for Romania U-18, Niculae was called up by coach Gheorghe Cristoloveanu for 2000 European Under-18 Championship qualifiers.He scored a brace on the first match against Bosnia and Herzegovina in a 3–1 win, but he was sent off in the second match against Bulgaria alongside teammates Adrian Olah and Tiberiu Bălan, ending his career for Romania U-18.Romania drew in the final match against Ukraine, thus failing to qualify for the play-off.