However, health officials said community testing may not be fully operational until the New Year.
Opening a debate in the Commons on the new system of levels of government for England, the Prime Minister said lateral flow tests were being rolled out across the country.
Asked by Liberal Democrat Leader Sir Ed Davey if tests would be available for anyone visiting family members over Christmas, he said: “People may take a lateral flow test.
“In general, the screening system is currently available for people who have symptoms.
“But I urge people who are worried about having to be in the company of the elderly or vulnerable to seek an early treatment test.”
His comments came after the head of operations for the mass community testing program warned on Monday that it would have to wait “January and beyond” before the program is fully rolled out.
General Sir Gordon Messenger told a Downing Street press briefing that the nature of the project would vary “from region to region and region to region” depending on readiness local.
“We are aware of the possibility that we will not be able to do all of this at the same time, but we feel that local authorities are at different levels of readiness and readiness to do it,” he said.
“And therefore, I can see this as an offering that will flow over time and into January and beyond.”
Gen Messenger said that to decide which areas to prioritize, they would look at infection rates and how long they have been living under tighter restrictions, as well as the maturity of their plans to deliver the tests.
Health Secretary Matt Hancock had previously pledged all care homes would be allowed to receive visitors before Christmas thanks to a new rollout of testing.
The Department of Health today announced that more than one million tests will be sent to home care providers over the next month, allowing safe indoor visits.
Visits will be able to take place at all levels and the first visits will begin on Wednesday, a spokesperson for the department said.
Mr Hancock said: “I know how difficult it has been for people living in nursing homes and their families to be separated for so long. The separation was painful but protected residents and staff from this deadly virus.
“I am very happy that we can now help reunite families and allow people to have meaningful contact with their loved ones by Christmas.
“This news was made possible by unprecedented advances in technology and testing capability, as well as additional Personal Protective Equipment (PPE) supplies.”