The court has restricted clinical drug trials countrywide after hearing evidence that new experimental medicines were being trialled on people, including children and the disabled, without their knowledge or permission.

''It pains us that illiterate people and the children of India are being used as guinea pigs by the multinational drug companies … uncontrolled clinical trials are creating havoc in the country,'' Justice R.M.Lodha said from the bench this month.

The court has imposed direct control of clinical trials on the health secretary, stripping authority from the government agency, the Drug Controller General, whose inaction, the court said, was allowing multinational pharmaceutical companies to run ''rackets'' across India.

''You have to protect the health of the citizens of the country. It is your obligation. Deaths must be arrested and illegal trials must be stayed.''

Precise figures are hard to find, but health organisations estimate that anywhere between 350,000 and 2 million people have been involved in the trials, some of which have been conducted using Australian government money.

As revealed in a Fairfax Media investigation, clinical drug trials are at the centre of a growing controversy in India, as evidence emerges before courts and, in government inquiries, of patients being put onto drug trials without their knowledge or consent, of patients dying and their families being left without compensation, and of doctors being paid generous commissions to enlist as many subjects as they can.

Figures from the drugs controller- general show that in 2011 there were deaths during clinical trials conducted by, or on behalf of, Novartis, Quintiles, Pfizer, Bayer, Bristol Mayer Squibb, and MSD Pharmaceutical.

Doctors are being told what to say - word for word - by the drug manufacturers in their assessment of the drugs they are supposed to be trialling, a parliamentary committee has found.