Police in Cardiff have said they issued 12 fines and a further 15 warnings during their first day of car checks to ensure people from outside Wales were not visiting the Welsh capital.
Officers stopped 110 drivers in the first 24 hours of the random checks scheme, which was introduced to stem the spread of coronavirus.
Twelve fixed penalty notices were handed out and a further 15 people received a warning - in which they were instructed to leave Cardiff - according to the force.
Those from high-risk areas outside Wales are currently prohibited from travelling into the country under new Welsh government rules.
The police were granted powers to stop and fine drivers from 9am on Friday. It is thought the move is specifically geared towards ensuring people from England do not cross the border.
People who were found to be breaching the legislation included a couple travelling from Essex who told officers they were heading to Cardiff to give family Christmas presents, and a group of nine people travelling in convoy to visit friends at university.
Police were given the temporary extra powers following widespread concerns that groups of people from locked-down areas of the UK, where pubs and bars are closed, were part of the crowds that gathered on central streets in Cardiff last weekend.
Cardiff and Vale of Glamorgan Chief Superintendent Wendy Gunney told reporters yesterday she “would like to thank the vast majority of people who are enjoying their weekend with caution and within the confines of the existing regulations” but warned that those not “adhering to the rules” were putting both their own lives at risk, as well as others’.
“The measures are in place are in place for a reason,” she said, before adding: “Our checks will continue throughout the weekend, and anybody blatantly flouting the rules, which have been made very clear, face being fined.”
SI Gunney confirmed that alongside vehicle checks, South Wales Police have had more officers on duty and that these changes will be in place until 5pm on Sunday - covering the final weekend of England's lockdown.
It comes as Mark Drakeford, Wales’ first minister, confirmed yesterday that restaurants and bars will be subject to stricter Covid restrictions in the run up to Christmas.
The new restrictions, which have not yet been finalised, will come into force from 4 December and are thought to be based on the system in some parts of Scotland where no alcohol can be served.
Cinemas, bowling alleys and indoor entertainment venues will also shut before the festive break. Mr Drakeford said action was needed as case rates continued to rise in the run up to Christmas.
The R rate in Wales is currently at around 1.4 but it must be below one for the number of cases to fall.