A police force launched a crackdown yesterday on businesses that display "No Traveller" signs.
North Wales Police is ordering its officers to take note of signs in pubs, shops and other public premises that advertise an anti-traveller policy.
They will then report the details to the Commission for Racial Equality, which will take legal action. North Wales Police claim it is the first such initiative in the UK.
Assistant Chief Constable Ian Shannon said: "This discrimination against gypsies and Irish travellers is widespread and completely unacceptable.
"We will help to tackle it by identifying the presence of 'No Travellers' notices and passing the information to the CRE so that action can be taken."
Chris Myant, director of the Commission for Racial Equality in Wales, said: "If these signs were to refer to any other group in our society, there would be uproar, yet 40 years after Parliament declared the practice to be unlawful we still see pubs, shops and other premises putting up 'No Travellers' or similar announcements.
"There must be zero tolerance for public expressions of prejudice of this kind."
Mr Myant added that he hoped others would join the police in reporting the signs.
He said: "The willingness of North Wales Police to join us in this work is confirmation of the force's determination to be proactive in working for good race relations.
"We hope others who are in a position to report to the Commission the presence of such notices will join in part-nership with us in helping to make the whole of Wales an area free of such abuses.
"Those responsible for premises need to deal with bad behaviour by customers on the basis of what those customers actually do, not simply who they are."