According to a report in the Sunday Times, Hancock used a private email account for government business.
Labour’s deputy leader Angela Rayner has called for an investigation into ministers using private email accounts.
Rayner said that “full transparency” is needed, and said the government is “rotten to its core”.
She suggested that the use of private emails could be in breach of the Official Secrets Act, Freedom of Information Act and data protection regulations.
The Sunday Times reported that Hancock and Lord Bethell, a health minister, had used private Gmail accounts to carry out government business.
Labour has also urged the government to recover any emails which might be relevant in an inquiry into the handling of Covid.
Deputy Labour leader and MP for Ashton-under-Lyne, Angela Rayner, said: “The buck doesn’t stop with Hancock and this matter is not closed. This government is rotten to its core.
“We need to know how wide this goes and how much government business is being conducted in secret.
“This shady practice has the potential to conceal vital information of public interest and cover up the waste of taxpayers’ money that has been given to friends of Conservative Ministers.”
Speaking to Sky News, Justice Secretary Robert Buckland said: “We should use Government emails, I think that’s very clear.
“I think the Cabinet Office, if they’re asked to look at this, they probably will be, will need to satisfy themselves that if that was the case then the material is available.”
Asked to comment on the report in the Sunday Times, a DHSC spokesman said: “All DHSC ministers understand the rules around personal email usage and only conduct government business through their departmental email addresses.”
Government ministers should always use their official email accounts to carry out government business, for transparency purposes.
Labour’s call for an investigation comes amid wider allegations of ‘cronyism’ relating to the issuance of PPE contracts to people linked to government during the pandemic
Labour is concerned that emails and other evidence which might be crucial for a future inquiry into the handling of the pandemic could be lost if private email addresses were used.
Hancock resigned as Health Secretary on Saturday after the Sun revealed that he had been having an affair with a married aide, in breach of Covid restrictions.