Wales vs New Zealand: Welsh face mask law to be policed on match-day trains
Wales' face covering law will be policed on match-day services this Saturday, ahead of Wales vs New Zealand.
Transport for Wales (TfW) warned passengers who do not wear a mask without a valid exemption they could be refused travel or removed from services.
It says British Transport Police (BTP) will remind passengers of the rules.
Social distancing will not be possible on match-day services, TfW added.
Anyone who forgets to wear a covering should speak to the company's staff for help.
In Wales train passengers and other users of public transport are required to wear a face covering by law.
This is stricter than in England, where face-mask laws ended in July, with the UK government only advising people to wear masks in crowded places.
In August there were concerns from some train users that the rules were being ignored with reports of passengers not wearing coverings on services.
A capacity crowd of 74,500 is expected to attend on Saturday for Wales opening game of the autumn internationals against New Zealand.
Transport for Wales is owned by the Welsh government - it is responsible for all of Wales' stations, as well as most of the country's train services.
TfW's Leyton Powell said: "Our crowd management and security staff will be working closely with BTP on match day to remind rugby supporters it is still a legal requirement to wear face coverings on public transport.
"Anyone refusing to wear a face covering without a valid exemption can be refused travel or removed from services."
The force's Inspector, Richard Powell, said: "We will have an increased presence at key locations, and officers will be reminding passengers of the requirement to wear a face covering on public transport in Wales, unless exempt."