The government and the doctors' union have agreed to continue negotiating until Wednesday.
The talks, hosted by conciliation service Acas, which started on Monday are seen as the last chance for the two sides to agree a deal.
They were set up following a series of strikes and included the first-ever full walk-out by doctors.
It comes after the government announced in February it would be imposing the contract from this summer after previous talks failed.
Discussions first started in 2012, but broke down in 2014, before Acas hosted talks at the turn of this year.
The main focus of this week's talks have been on Saturday pay, although the British Medical Association (BMA) team has also been raising other issues, including funding the government's seven-day NHS policy.
If these talks fail, the government has indicated it will push ahead with the imposition of the contract.
Hospitals are due to start sending out contracts for positions from the end of this month.
These will be for those medics graduating from medical school, but over the course of the next 12 months much of the rest of the 55,000-strong workforce will be moved on to the new terms and conditions.
Ministers have argued the new contract, which makes it cheaper to rota junior doctors at weekends, is needed to improve care.
Acas chair Sir Brendan Barber said the talks had been conducted in a "constructive and positive atmosphere" and some real progress had been made.
"This is a strictly time limited extension and represents a final opportunity to find an agreement as the basis for the resolution of this difficult dispute."
He said neither the BMA or government would be making any statement.
When it entered the talks, the government agreed to put imposition of the contract on hold, while the doctors' union suspended its threat of further industrial action.
Under the terms of the new contract, basic pay is to be increased by 13.5% on average, but other elements of the pay package are to be curbed, including what constitutes unsociable hours.
Day hours on a Saturday will be paid at a normal rate, while extra premiums that are being offered for the rest of the weekend are lower than what is currently paid.
As a result of the dispute between the government and the BMA, there were four strikes by junior doctors in England affecting routine - but not urgent care - between January and early April.
At the end of April there were two one-day strikes affecting all forms of care, including emergencies - the first such action in the history of the NHS.
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Last ditch talks to reach a deal on the junior doctors contract in England are being extended into next week.