An amber Cold-Health Alert (CHA) will be in place for parts of England until noon on Friday, January 12.
The areas affected are the North West of England, West Midlands, East Midlands, South East of England and South West of England.
The UK Health Security Agency (UKHSA) and the Met Office said a yellow CHA remains for the North East of England, Yorkshire and the Humber, East of England and London.
All regions had previously been placed under a yellow alert from 9:00a.m on Saturday, January 6, with the Met Office forecasting a period of lower-than-average temperatures across the weekend just passed and this coming week.
There is currently a yellow warning for ice in south Wales and the south of England. It will be in place until 3:00a.m tomorrow (Tuesday, January 9).
Head of extreme events and health protection at UKHSA, Dr Agostinho Sousa, said: “With the Met Office forecasting drops in temperature across the United Kingdom into next week, it is important to check in on the wellbeing of those most vulnerable to the cold.
“Cold weather can increase the risks of heart attacks, strokes, and chest infections, so it can have a serious impact on health, particularly for older people and those with pre-existing health conditions.
“Temperatures are expected to turn particularly cold overnight, as we would expect at this time of year.
“If you have a pre-existing medical condition or are over the age of 65 it is important to try and heat the rooms where you spend most of your time, such as your living room or bedroom, in the coming days.”
Under the new CHA system introduced by UKHSA and the Met Office, an amber alert means that cold weather impacts are likely to be felt across the whole health service for an extended period of time, with potential for the whole population to be at risk and where other sectors may also start to observe impacts, indicating a coordinated response is required.