A decision on restricting travel into Wales from areas of high Covid prevalence in the UK will be made in the next few days, the health minister has said.
Vaughan Gething told BBC Breakfast decisions would be made about using the Public Health Act 1984 legislation.
It would work in a similar way to the "stay local" rule during the first lockdown, which police enforced.
People from England were turned back from Wales under those regulations.
Mr Gething said it had been "disappointing" to hear there would be no legal protection brought in by the UK government to prevent people in English hotspot areas from travelling outside their region, as is the rule in the parts of Wales currently under local lockdowns.
Ministers are worried about people travelling to holiday hotspots, like Pembrokeshire, Powys and Anglesey, which are not currently under Wales' lockdown restrictions.
First Minister Mark Drakeford has written twice to Prime Minister Boris Johnson to ask for this to happen.
Under the new three-tier system of alerts, areas of England will have different restrictions depending on their level of cases but there are no travel restrictions on those in the highest area (currently affecting Merseyside).
"We're already talking with our lawyers about how we use our powers under the Public Health Act 1984 to introduce a range of restrictions for higher prevalence areas from any part of the UK," Mr Gething said.
"This isn't aimed at one part, one country of the UK. It's the highest prevalence areas to protect our low prevalence areas. It's a protective measure.
"In the next few days, the first minister and I will have to make a choice about how we keep Wales safe."
David Robertson, who owns The Bull in Beaumaris on Anglesey, said restrictions on travel would be putting a "metaphorical barrier" around his business because he relies so heavily on people travelling from surrounding areas.
"It's a bit like barricading the front door," he said.
"I have 50 staff to pay and the government is saying 'don't go to the Bulls Head'. So I don't know how I am supposed to cope with winter's business with that kind of environment."
How would travel restrictions work?
Mr Gething said the country had previously been through this with the stay local guidance introduced in Wales in the earlier months of the pandemic.
"That was enforced by police, they were able to identify cars from outside the area," he said.
"They were able to engage and educate those people and the great majority turned back. Those who refused did get issued with fixed penalty notices, and if they stayed, further notices.
"It can be enforced successfully.".
He said it would have been better to have a "collegiate approach" across all four UK nations.
"It's not just that the prime minister has said what he's said (about not bringing in travel restrictions) but we haven't had a response to either letter and it would have been much more preferable to set out a reasoned answer in writing between the first minister and the prime minister," he added.
"We're going to have to act on the basis that Boris Johnson does not think it appropriate to protect low prevalence areas of the United Kingdom from the very highest areas within England itself."
Will Wales have a circuit breaker?
Asked about a "circuit breaker" - a short period of higher lockdown restrictions to help slow or lower the spread of the virus - he said it was a "potential way forward".
Northern Ireland has just announced a circuit break which will see schools closed for an extra week from Monday in addition to the half term break, and hospitality businesses limited to takeaway and home delivery services for four weeks from Friday.
Mr Gething said: "We're actively considering [it] and over the coming few days we're going to need to make some choices about whether we're going to do that or not.
"Many people are pointing to the school half term as a potential way to introduce a break if we were going to do so.
"The next few days will be very important but we're getting specific advice tailored to Wales to understand what that might look like."