Resident doctors in ‌England have begun a six-day walkout after rejecting an offer the government says will not get better, with the British Medical Association ‌saying it fails to reverse years of pay erosion and staffing pressures.

The strike action during the Easter holiday period is due to run until the morning of April 13 after a 48-hour ultimatum from Prime Minister Keir Starmer passed without agreement.

The government has now withdrawn a pledge to fund 1000 additional speciality training posts that it said had been contingent on the deal being accepted.

Health ‌minister Wes Streeting ‌said the government ⁠was not prepared to spend money needed for patient services on a settlement it viewed ​as unaffordable, estimating the strike would cost the health service about Stg50 million ($A96 million) a day, or Stg300 million over the six-day walkout.

Speaking on Times Radio on Tuesday, Streeting said resident doctors had secured the largest pay uplift of any public sector group under the Labour government, but had rejected the offer without putting forward a counter-proposal.

Streeting had said the offer "doesn't get better ⁠than this" when urging the union to reconsider in March.

The BMA represents ‌about 55,000 ​of the resident doctors - formerly known as junior doctors - who make up nearly half of the medical workforce.

Since early 2023, ‌the BMA has held more than a dozen rounds of industrial action over pay, strike action that successive governments has ​blamed for frustrating efforts to reduce waiting lists in the state-run service.

The union says the government's offer on pay and workforce does not go far enough to address long-standing concerns, including historical below-inflation pay increases.

The pay offer includes a ​3.5 per cent ​increase in 2026, which the government said would represent ​an above-inflation rise, and take total pay increases over three years ‌to about 35 per cent, plus reimbursements of mandatory exam fees, which can cost doctors thousands of pounds.

Jack Fletcher, chair of the BMA's resident doctors' committee, has said the union was concerned the level of investment in the deal had been reduced, the proposed reforms were spread over several years, and uncertainties remained over the implementation of new training posts.