Monkeypox will be included as a notifiable disease from June 8, the UK Health Agency said.
It means that all doctors in England should notify their local council or the local health protection team (HPT) if they suspect a patient has smallpox.
Laboratories must also notify the UKHSA if the virus is identified in a laboratory sample.
It comes after the total number of confirmed cases of smallpox in the UK reached 302 on Monday.
Wendi Shepherd, Director of Incidents at Monkeypox at UKHSA, said: “Rapid diagnosis and notification is key to stopping transmission and containing any other spread of Monkeypox. This new legislation will help us and our healthcare partners to quickly identify, treat, and control the disease.
“It also supports us with the rapid collection and analysis of data that allows us to detect possible outbreaks of the disease and quickly track close contacts, while also providing vaccinations when appropriate to limit transmission.”
Professor David Heymann, a professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine (LSHTM), said that making monkeypox a notifiable disease “suggests a desire to make sure that has reports from all sectors – public and private – and from all parts of the NHS. “
He added: “He suggests that the government wants to focus surveillance on the entire population, not just the risk groups identified so far.
“This will allow a clear identification of all risk groups and help to better understand the epidemiology and extent of the spread.”
The UKHSA has insisted that the risk to the general population “remains low” because the virus, which is transmitted by close physical contact, does not spread easily.
However, it can live on surfaces such as sheets or towels.
People are advised to take care of unusual rashes or ulceration.
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1:39 It’s like catching monkeypox
The government did not release updates on the number of daily cases of smallpox during much of the holiday weekend, but 11 cases were reported on Thursday.
Last week, UKHSA data said more than 50% of cases in England were found in gay, bisexual or other men who have sex with men.
Most cases of smallpox have occurred in people between the ages of 20 and 49.
Of the 190 cases reported between 6 and 31 May, 111 cases were men known to be gay, bisexual or other men who have sex with men, according to the UKHSA.
A UKHSA spokesman said there would be no update on Monkeypox case numbers today, and the next update will be released on Wednesday.