The first minister of Wales says he will not "lightly" put aside an agreement for relaxed coronavirus rules over Christmas.
Pressure is growing on the four UK governments to reconsider plans to allow three households to meet between 23 and 27 December.
But Mark Drakeford said harm would be done "in either direction".
Talks between the four nations ended without a decision on Tuesday - they are expected to reconvene on Wednesday.
Politicians from Mr Drakeford's own Welsh Labour party have expressed concern over the relaxed rules, while Plaid Cymru called for the rules to be reviewed.
Plaid leader Adam Price called for "urgent consideration" of a level 4 lockdown in areas of Wales with high Covid rates before 28 December.
Meanwhile Welsh Conservative health spokesman Andrew RT Davies said "powerful arguments" were being made to tighten the rules amid rising cases.
The current plans had been agreed between the UK government and ministers in Scotland, Wales and Northern Ireland.
Labour leader Sir Keir Starmer urged Prime Minister Boris Johnson to convene an emergency Cobra meeting to review the plans.
The case rate in Wales is currently 416.5 cases per 100,000 people over seven days.
First ministers from the three devolved nations and cabinet minister Michael Gove discussed the subject on Tuesday.
A source said talks would continue the next day and would confirm a way forward: "A range of options were under discussion, including the status quo.
"The four-nations approach is still very much the Welsh Government's preferred option - that was emphasised in the meeting."
But BBC political correspondent Nick Eardley reported there were no plans to change the regulations covering Christmas in England.
There is likely to be tougher guidance given in the coming days to reflect the current situation, he added.
A source told him there was "broad recognition" that a "commitment has been made to people and they will expect us to honour it - but there is a need to be stronger and clearer in guidance and messaging".
There were discussions on travel over the Christmas period, but no decisions made, the source added.
Earlier in the day Mr Drakeford said it was a "grim" choice, and he had received "heartrending" pleas from people not to reverse the decision.
"Yet we know that if people do not use the modest amount of additional freedom available to them over the Christmas period responsibly, then we will see an impact of that on our already hugely hard-pressed health service."
Mr Drakeford said he preferred to have rules in place rather than a "free-for-all, in which we have a situation where people simply aren't willing to go along with what is proposed and therefore make the rules up for themselves".
He added: "If we seek to prevent people from meeting over Christmas a different sort of harm will be done to people's sense of mental health."
'Situation has deteriorated'
Later, Mr Drakeford said "a decision on further restrictions" after Christmas "cannot be long delayed".
In a debate on the new alert level system, he said: "Last week I said if matters do not improve then a move to level four restrictions was inevitable.
"Since then, far from improving, the situation has deteriorated and the pressure on our NHS and social care has intensified.
Mr Drakeford has warned of possible lockdown-style restrictions after the festive period.
Welsh Labour concern
Gower Labour MP Tonia Antoniazzi called for the plans to be reconsidered.
"There is always the concern some people will just carry on as normal but I would welcome a strong message," she said. "It is difficult to know what to do, but I am very, very apprehensive about the five days."
Her Rhondda colleague Chris Bryant has said relaxing the Covid-19 restrictions would be a "mistake" that could cost lives and disrupt the vaccination programme.
"It may be too late to change it legally and I don't want to criminalise anyone, but we could all take our own measures and decide to limit our contacts severely."
In the Welsh Parliament, Torfaen Member of the Senedd (MS) Lynne Neagle called for tougher restrictions "now" and feared the Christmas plans "will come at the cost of more hospital admissions and further deaths".
"I just don't think that is a price worth paying when we have the light of a vaccine at the end of this very dark tunnel we are in," she told the debating chamber.
What has the opposition said?
Paul Davies, the leader of the Welsh Conservatives in the Senedd, said: "We're at a point where we must recognise the current intervention is not stemming the transmission of the virus."
He told the Senedd in light of the increased pressure on our NHS, "it's imperative that the Welsh Government make a decision on the next steps to control the virus because people, businesses and our front-line workers need to know what is happening as soon as possible to plan ahead".
There is a "strong case" to review the Christmas agreement, according to Plaid Cymru leader Adam Price.
He said Wales was "facing a worsening situation and ministers are losing control. They must act to protect the NHS which is in danger of being overwhelmed as the number of Covid-19 cases reach record levels".
Clear guidance that only two households should be mixing over Christmas "with compassionate exceptions" should be considered, he said.
He added that "urgent consideration" must be given to introducing level 4 restrictions in "areas of high Covid, in particular in the south of Wales, without delay and before December 28th if that is what the situation requires".
Level 4 restrictions are equivalent to a lockdown under Wales' Covid plan, announced on Monday.
Welsh Conservative health spokesman Andrew RT Davies said: "The Welsh Government, as a matter of urgency, needs to confirm the rules around Christmas to allow people to prepare and, importantly, by making a clear commitment this will support people's mental and physical wellbeing at a particularly difficult time for many."