Dr Johann Malawana, the BMA's junior doctor committee chairman, said: "The decision to impose a contract is a sign of total failure on the Government's part."
He added: "Junior doctors already work around the clock, seven days a week and they do so under their existing contract. If the Government want more seven-day services then, quite simply, it needs more doctors, nurses and diagnostic staff, and the extra investment needed to deliver it.
"Rather than addressing these issues, the Health Secretary is ploughing ahead with proposals that are fundamentally unfair.
"This is clearly a political fight for the Government rather than an attempt to come to a reasonable solution for all junior doctors. If it succeeds with its bullying approach of imposing a contract on junior doctors that has been roundly rejected by the profession it will no doubt seek to do the same for other NHS staff."
He continued: "Our message to the Government is clear: junior doctors cannot and will not accept a contract that is bad for the future of patient care, the profession and the NHS as a whole, and we will consider all options open to us."
Thousands of junior doctors across Yorkshire and Lincolnshire are taking part in a strike as part of a bitter dispute over a new contract.
Junior doctors across the region are manning the picket lines in what is become an increasingly bitter dispute about contracts.
Thousands of junior doctors in England are to begin strike action today, with patients being warned to expect major disruption.