Dr Ellen McCourt, who chairs the BMA junior doctors' committee, said: "Junior doctors still have serious concerns with the contract, particularly that it will fuel the current workforce crisis, and that it fails to treat all doctors fairly".
A spokesman for the Academy of Medical Royal Colleges said they are "disappointed" at the prospect of further sustained industrial action.
They added: "Despite our efforts to work with the Secretary of State to resolve this dispute, the Government has failed to listen, leaving us with no option but to take more industrial action".
She added: "We have a simple ask of the government: stop the imposition".
A Department of Health spokesperson said that as doctors' representatives, the BMA should be putting patients first, "not playing politics in a way that will be immensely damaging for vulnerable patients".
They say it will lead to unsafe conditions as doctors are overworked and many claim his plans are an attempt to privatise the NHS by the backdoor.
"Because of the duration of this latest period of industrial action it is, unfortunately, inevitable that we shall have to postpone some outpatient appointments and routine procedures".
More than 100,000 operations and one million appointments are expected to be cancelled during this month's strike alone.More news: Have Brooklyn Beckham And Chloe Grace Moretz Broken Up?
"Patient safety is our priority and to ensure high quality and safe care and welfare can be maintained throughout the period".
But there are now growing questions about the level of support there is amongst the wider profession for the strikes, despite the BMA saying it is "absolutely behind" the decision for further action.
Urging the two sides to resume talks, Ms Murphy said: "Many patients may be very unwell or vulnerable and so we can not predict the distress or pain this will cause...the Government and the BMA must appreciate they are in a privileged position: words seem to come easy and cost very little to them, but to the public it is costing them a great deal in lost working days, anxiety, pain and uncertainty".
Chief executive Katherine Murphy told the Press Association: "From a patient's point of view it is obviously catastrophic news - the scale of the industrial action is unforgivable".
And he claimed that almost all Health Secretaries are unpopular -even the legendary NHS founder Nye Bevan.
Labour's Shadow Health Secretary Diane Abbott said the strike was "always likely", given the "intransigence" of the Government.
Health Secretary Jeremy Hunt wants an NHS that offers a full seven-day service because at the moment routine operations do not take place at weekends. Today, the Health Secretary sought to deepen the divisions by warning that thousands of sick people would suffer pain and inconvenience because of the "totally irresponsible" walkout.
She responded: "It is really proportionate to claim that by imposing the new contract we will suddenly manage to deliver seven-day services?" I was previously uncomfortable about the imposition of the contract on junior doctors, but now believe there is little alternative.