The group hopes to secure a judicial review over the potential impact on patient safety and the future of the NHS of imposing the contract, and have now raised around £70,000 to fund the action.
BMA leaders have also demanded a judicial review over health secretary Jeremy Hunt's decision to impose the contract after talks collapsed. But the union's challenge focuses on concerns that the government failed to carry out an equality impact assessment, while the new legal action is wider in scope.
The government's lawyers have said that the BMA bid for a judicial review was 'bound to fail'.
The latest legal challenge comes just days after the first of three 48-hour walkouts by junior doctors in protest over the contract imposition.
Junior doctor strikes
Dr Ben White, one of the doctors behind the legal challenge, said: 'Forget the lies and propaganda. The imposition of the junior doctor contract affects all NHS service users. Staff know that the lack of workforce planning, lack of cost modelling, plus rota and staffing issues, create a perfect storm where patient safety will inevitably be compromised.
'We must challenge this contract in the High Court. A judicial review would consider all relevant factors and hold the government accountable for decisions it has made. Ultimately, this is about public safety.'
The government has criticised the BMA over junior doctor strikes. Speaking ahead of the 48-hour walkout last week, a DH spokeswoman said: 'Patients have so far seen more than 19,000 operations cancelled as a result of the BMA's irresponsible and unjustified industrial action.
'The new contract, 90% of which was agreed with the BMA, and endorsed by senior NHS leaders, is a very good deal for doctors and the NHS. It will mean an average 13.5% basic pay rise with a cap on the number of long shifts worked to improve safety. We urge junior doctors to look at the detail of the contract and the clear benefits it brings.'
Photo: Alexander Christie