Covid: South Wales Police to carry out Christmas vehicle checks
Random vehicle checks will be carried out by South Wales Police officers over the festive period.
Under Alert Level Four, people are expected to stay at home and not leave without a reasonable excuse.
Rules will only be relaxed on Christmas Day, when two households will be able to mix, along with one other single person.
Powers came into force at 07:00 GMT on Tuesday and will last until 4 January, when they will be reviewed.
Officers will check reasons for travelling, with a spokesman saying they will concentrate on "the four Es".
These are firstly engaging with the public, explaining the restrictions and encouraging voluntary compliance.
Only those believed to be in blatant breach of the rules will face enforcement action.
It is not the first time police have been given such powers, with officers conducting random checks in Cardiff during November's firebreak.
Under the coronavirus fixed penalty notices system, people can be fined £60 for a first offence, which increases to £120 for a second offence and continues to double for repeated offences, up to a maximum of £1,920.
If a driver is prosecuted however, a court can impose an unlimited fine.