Such action has been taken by the UK government to protect tax regimes and taxpayers in the past and the Welsh Ministers wish to be able to take similar action.
Cymerwyd camau o'r fath gan Lywodraeth y DU i ddiogelu cyfundrefnau treth a threthdalwyr yn y gorffennol ac mae Gweinidogion Cymru am allu cymryd camau tebyg.