NTSC game on PAL console

Hi, I have a modchipped SCPH-90002 PS2 slim console (PAL, Australia). I would like to play a game that only had an NTSC release, Final Fantasy Tactics for PS1. The game is running but the video output is black and white, and there is other graphical glitching. I think I have seen this before when there is PAL/NTSC mismatch.
Is there any way to fix this? I am running the composite video output through a cheap HDMI adaptor.