Doctors' action: Simon Burns and Hamish Meldrum
21 June 2012 Last updated at 13:52 BST
The British Medical Association chairman said doctors were aiming to "minimise the impact on patients" as they boycott non-urgent care on Thursday in a dispute over pensions.
Hamish Meldrum said doctors were having to pay twice as much as some civil servants, had already agreed to work harder and pay more for pensions, and were in the third year of a pay-freeze.
Health Minister Simon Burns denied the government had reneged on a previous deal, and said it was offering a "fair deal"- accepted by other health workers - and would not be changing it.