Covid vaccinations are to become mandatory for care home staff under plans to be announced by ministers, as they consider extending the move to all NHS staff.

The controversial measure sets up a likely battle with staff in both services and could lead to the government being sued under European human rights law or equalities legislation for breaching the freedom of people who work in caring roles to decide what they put into their bodies.

The Guardian understands that ministers will confirm they are pushing ahead with compulsory vaccination for most of the 1.5 million people working in social care in England, despite employer and staff organisations in the sector warning that it could backfire if workers quit rather than get immunised. Under the plans those working with adults will have 16 weeks to get vaccinated or face losing their jobs.

The government is also keen to make it mandatory for the 1.38 million people who are directly employed by the NHS in England to get vaccinated against Covid-19 and winter flu – proposals that have already been criticised by groups representing doctors, nurses and other staff.

The Department of Health and Social Care (DHSC) will in the coming days launch two separate consultation exercises into making Covid and flu jabs mandatory for NHS staff. But ministers including the health and social care secretary, Matt Hancock, believe the arguments in favour of protecting patients from potentially infectious staff now outweigh those that allow health workers the right to choose whether or not to have either immunisation.

The British Medical Association, which represents doctors, warned on Tuesday that while they want all NHS staff to get jabbed, “compulsion is a blunt instrument that carries its own risks”.

“While some healthcare workers are already required to be immunised against certain conditions to work in certain areas, any specific proposal for the compulsory requirement for all staff to be vaccinated against Covid-19 would raise new ethical and legal implications,” it said. Staff in some areas, such as surgery, are already obliged to get vaccinated against hepatitis B, for example.

The NHS Confederation, which represents health service trusts in England, has already described plans to move to compulsory immunisation as “unhelpful” and cautioned that hospital bosses are “unlikely to welcome a move to mandating the vaccine for NHS staff”.

One NHS boss said: “If you are going to go down this route of mandation for NHS staff, you will get into a direct confrontation with a group of staff who you’re forcing to do this at a time when you’re denying them a decent pay rise but also saying how much you love them.

“The government hasn’t thought through the consequences of this. Hospital trusts could end up having to suspend or even dismiss members of staff who continue to refuse to be vaccinated against Covid in defiance of a policy requiring them to get jabbed,” the senior figure said.

The government is pressing ahead with mandatory Covid vaccination even though the latest figures show that, as of 6 June, 89% of NHS staff had had their first dose and 82% had had both.

Take-up has been lower among social care staff. Vaccination statistics show that 83.7% of staff in adult care homes had received at least one dose by 6 June and 68.7% had been double-jabbed.

Hospital bosses are also worried that the government’s apparent readiness to force staff to get vaccinated will lead to them having to have “difficult conversations” with black and minority ethnic staff, as take-up rates are lower among them than among white NHS personnel. Persuading young female employees worried about the Covid vaccines affecting their fertility to get immunised has also been a problem in many trusts.

Ministers are keen to reduce the spread of Covid-19 in care homes and hospitals by staff who are infected. The minutes of the latest meeting of the government’s Scientific Advisory Group on Emergencies show that it is keen to see hospitals take action to reduce hospital-acquired Covid, which the Guardian recently revealed had led to the deaths of at least 8,700 inpatients since the pandemic began in March 2020.

The DHSC also believes it would be inconsistent to mandate vaccination for care home workers but not NHS staff, given that some of the latter – such as GPs, physiotherapists and district nurses – often go into care homes to care for residents.

The Royal College of Nursing is also opposed to mandatory jabs for NHS staff. “It’s essential that staff have the opportunity to fully understand and have autonomy over what goes into their bodies,” Dame Donna Kinnair, its chief executive, said previously. “It is counterintuitive to introduce a policy which could affect recruitment and retention in a sector which is already chronically understaffed.”

However, the DHSC’s drive to make vaccination a contractual requirement for health workers has been boosted by NHS England, which had privately been concerned about the plan, changing its stance recently and deciding not to oppose the move.

Opinion is split in the NHS over mandation. Laura Churchward, the director of strategy at University College London hospital, one of the NHS’s biggest trusts, recently told the Health Service Journal that: “We probably have to accept it will have to become mandatory for roles with exposure to patients.”

And one senior official at a health union said: “The public are going to think that it’s the right thing to do – that all NHS staff should have it – because they are going to care for someone.”

A DHSC spokesperson said: “Vaccines are our way out of this pandemic and have already saved thousands of lives, with millions of health and care staff vaccinated.

“Our priority is to make sure people in care homes are protected and we launched the consultation to get views on whether and how the government might take forward a new requirement for adult care home providers, looking after older people, to only deploy staff who have had a Covid-19 vaccination or have an appropriate exemption.

“The consultation ended on Wednesday 26 May and we will publish our response in due course.”