Health Secretary Jeremy Hunt has said it is "very, very disappointing" that thousands of junior doctors plan to go on strike.
Mr Hunt said the NHS would do all it can to keep patients safe if industrial action goes ahead but told the BBC there was a need to bring in seven-day services.
He said: "This is very, very disappointing news today.
"We want to be able to promise NHS patients they will get the same high-quality care every day of the week.
"Study after study has shown that our mortality rates at weekends are too high.
"We put a very fair offer for doctors that would see pay go up for three-quarters of junior doctors.
"We wanted to talk about this to them but, in the end, they've chosen to strike.
"We will have to put in place contingency plans to make sure patients are safe over a very, very busy period for the NHS."
Some 98% of junior doctors balloted by the British Medical Association (BMA) voted in favour of strikes, with 2% against and 11 spoilt ballot papers.
More than 37,000 doctors were balloted by the BMA, and 76% took part in the vote.
The BMA said it was still keen to avoid strike action and had approached the Advisory, Conciliation and Arbitration Service (Acas) for talks with Mr Hunt and NHS Employers, which is running negotiations for the Government.
If a strike goes ahead, doctors will take action over three days, providing emergency care only for 24 hours from 8am on December 1, followed by full walkouts from 8am to 5pm on December 8 and 16.
There is expected to be mass disruption to the NHS, with hospitals forced to cancel outpatient clinics and non-urgent operations.
Dr Mark Porter, chair of the BMA council, said: "We regret the inevitable disruption that this will cause but it is the Government's adamant insistence on imposing a contract that is unsafe for patients in the future, and unfair for doctors now and in the future, that has brought us to this point.
"Patients are doctors' first priority, which is why, even with such a resounding mandate, we are keen to avert the need for industrial action, which is why we have approached Acas to offer conciliatory talks with the Health Secretary and NHS Employers to clarify the conflicting information coming from Government over the past weeks."
Prime Minister David Cameron's official spokeswoman said: "Clearly it is regrettable that the BMA have decided to go ahead with this action that will put patient safety at risk.
"We want to sit around a table and negotiate. We would urge the BMA , rather than striking, to return to negotiations."
The new contract is set to be imposed from next summer on doctors working up to consultant level.
Mr Hunt tried to avert strikes with a fresh deal, including an 11% rise in basic pay.
This is offset by plans to cut the number of hours on a weekend that junior doctors can claim extra pay for "unsocial" hours.
Currently, 7pm to 7am Monday to Friday and the whole of Saturday and Sunday attract a premium rate of pay.
Under the new plans, a higher rate would run from 10pm to 7am Monday to Friday, and from 7pm on Saturday evenings - a concession on the previous 10pm.
Other proposals are to replace the GP pay supplement - without which GPs would be paid on average around a third less than hospital trainees - and replace it with a "flexible pay premium".
Mr Hunt argues that, under the new deal, just 1% of doctors would lose pay and those would be limited to doctors working too many hours already.
He said maximum working hours per week would fall from 91 to 72.
Dr Johann Malawana, the BMA's junior doctor committee chairman, has said the increase in basic pay is misleading due to the changes to pay for unsocial hours. He said this devalues the vital work junior doctors do in the evenings and at weekends.
The BMA has argued the Government could avoid strikes by offering several assurances and lifting the threat that the contract will be imposed.
Shadow health secretary Heidi Alexander said: "Jeremy Hunt needs to take responsibility for the fact that this is the first time in 40 years that junior doctors have voted to take such significant industrial action.
"There is clearly huge anger about the way in which these negotiations have been handled by the Government.
"It is imperative that, in the next 10 days, Jeremy Hunt and David Cameron find a way to avoid a strike."