All GP practices in England will open on Saturdays under a contract update, according to reports.
They will also have to offer bookable weekday evening appointments from 6.30pm to 9pm, a letter from NHS England said.
GPs will be required to provide a 'range of general practice services' under a 'full multi-disciplinary team', including for services such as screening, vaccinations and health checks.
Although some practices across the country already offer late-night or weekend services, this will become mandatory from October 1 this year.
The plans were set out in a letter sent yesterday by the director and medical directors of primary care at NHS England and NHS Improvement setting out general practice contract arrangements for the next financial year.
More evening and weekday appointments for GP services were previously agreed in 2019, though the implementation was delayed due to the Covid pandemic.
The British Medical Association said it was 'bitterly disappointed' by the changes.
It added it had been 'blindsided' by the announcement.
The union's GP committee chair Dr Farah Jameel said: "We are bitterly disappointed that NHS England has chosen to ignore the appeals from the profession and the needs of patients in today’s letter."
She added that NHS England seemed committed to following a plan laid out three years ago and which failed to address the current pressures faced by GPs.
NHS chiefs last month told GPs to 'restore routine services' again as restrictions eased.
Health Secretary Sajid Javid ordered doctors to offer more face-to-face appointments after data revealed just 60 per cent of consultations in England in January were in-person, compared to 61 per cent in December.
