The Fundraising Regulator has launched the Fundraising Preference Service in Welsh.
The regulator said the Welsh-language version of the FPS website, accessible through the existing site, would meet the needs of Welsh speakers who wanted to control their fundraising communications from charities.
The service, which was launched in July, allows people to block mail, email, text-message and phone contact from named charities.
The Fundraising Regulator, which manages the FPS, said it had handled almost 13,850 suppression requests from almost 5,000 people in England, Wales and Scotland to the end of last year.
People in Scotland can make suppression requests only relating to charities that are primarily registered in England and Wales. The service is expected to be expanded to cover charities in Northern Ireland this year.
The regulator said that more than a fifth of requests had been made on behalf of another person, indicating that the service was being used to help vulnerable people.
Stephen Dunmore, chief executive of the Fundraising Regulator, said launching the Welsh version of the FPS was an important milestone.
Ruth Marks, chief executive of the umbrella body the Wales Council for Voluntary Action, said the move was a "very welcome development".