Immigration Minister Scott Morrison says he did not "backflip" when reversing his freeze on protection visas for asylum seekers, arguing the regulation was no longer necessary because he has since introduced stronger rules.

But legal experts and the Greens say Mr Morrison is engaged in legal "trickery" and his new regulation would either be struck down by the High Court or reversed when the Senate reconvenes in February.

The legal battle began on December 2, when Mr Morrison, infuriated that Labor and the Greens were stopping him introducing temporary protection visas, decided to put a freeze on all protection visas until July 2014.