Boris Johnson has faced calls to explain how regions can have their coronavirus alert level and restrictions lowered.
He was urged by Sir Keir Starmer to set out exactly what areas need to do to be downgraded from Tier 3 to Tier 2, or Tier 2 to Tier 1.
And a Conservative MP, whose constituency in York had tougher measures imposed last week, said the prime minister needed to be “more open” about the evidence base for that decision.
Mr Johnson has been resisting calls from the Labour Party and his scientific advisers, known as SAGE, to bring in a “circuit breaker” – effectively a short national lockdown.
He said in the Commons on Wednesday that a regional approach was better and would not unfairly impact parts of England with lower COVID-19 infection rates.
But Sir Keir said a national framework for what financial support councils get for going up a tier should be laid out instead of “grubby, take-it-or-leave it” deals, and asked for clearer answers on how areas can also move back down a tier.
“Instead of being a solution, Tier 3 is a gateway to weeks and weeks – more likely months and months – of agony from which there’s no likely exit,” he said.
“Can the prime minister not see the problem if there isn’t a clear exit?”
Mr Johnson said the R rate – the average number of people someone with coronavirus infects – will be taken into account along with admissions to hospital and “other data”.
“Areas that have gone into Tier 3 I believe are already making progress,” he replied.
“We are pursuing a local, regional approach, which is the sensible approach for this country.
“That’s what the epidemiology supports, it’s what the deputy chief medical officer supported last night.”
Mr Johnson accused Sir Keir of being “incoherent” for “attacking local lockdowns when he wants to plunge the whole country back into a damaging lockdown for weeks on end”.
But he was also tackled by Tory backbencher Julian Sturdy, who said the government should be “more open in communicating the evidence base for York going into Tier 2” and “outline a road map for the city’s return to Tier 1”.
And he urged the prime minister to “consider creation of specific support for York’s hospitality industry, suffering losses from the limbo that Tier 2 is creating”.
Mr Johnson said in York, infections are up to 279 per 100,000 people and “we must get it down”.
But he added: “We can get it down through the package of measures we’ve described, you can see in areas where people are complying with the guidance that it is having an effect.”