The prime minister is to make a statement to MPs on Monday giving details of new restrictions to slow the spread of coronavirus in England.
A letter from Boris Johnson's adviser to MPs in the North West seen by the BBC says it is "very likely" some areas will face further restrictions.
But some regional leaders warn the new plan for a three-tier local lockdown system will only create more confusion.
It comes as a doctors' union calls for clearer and more stringent rules.
Under the new restrictions, pubs and restaurants could be closed in parts of northern England and the Midlands - where some of the highest numbers of cases are occurring - while a ban on overnight stays is also being considered.
It is understood that the most severe measures - imposed for areas in tier three - would be agreed with local leaders in advance.
The details of each tier, including the level of infection at which an area would qualify for it and the nature of the restrictions, are being debated this weekend.
Labour leader Sir Keir Starmer said it was grossly irresponsible for anonymous government sources to tell newspapers on Thursday about plans for further restrictions on millions of people, without any detail, consultation or statement from the prime minister.
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The letter to the MPs from Downing Street's chief strategic adviser Sir Edward Lister says the government is hoping to "finalise these details as soon as possible" amid "rising incidence in parts of the country".
It also cites the "engagement that is taking place today and during the course of the weekend with local authority leaders in your region".
Sir Edward says the set of measures being discussed "present difficult choices. We must seek to strike the right balance between driving down transmission, and safeguarding our economy and society from the worst impact".
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