One in five abortion clinics are breaking the law by "pre-signing" abortion consent forms, the government said.
Spot checks were carried out at more than 250 abortion clinics and found evidence of blank forms being signed in anticipation of patients seeking a termination.
The law states that two doctors must agree for a woman to have an abortion, except in emergencies.
There is no law that the doctors must see the woman, only that they are aware of her circumstances and that she wants to go ahead with the procedure.
Nurses, counsellors and other healthcare professionals can assess the woman before the forms are signed.
Of the 250 clinics that were investigated by the Care Quality Commission (CQC), 15 to 20 percent may be breaking the law by pre-signing consent forms.
Health secretary Andrew Lansley said he was appalled at doctors pre-signing abortion consent forms after he ordered inspections at 250 clinics.
Lansley said: "I am shocked and appalled to learn that some clinics - which look after women in what are often difficult circumstances - may be allowing doctors to pre-sign abortion certificates.
"This is contrary to the spirit and the letter of the Abortion Act.
"The rules in the Abortion Act are there for a reason - to ensure there are safeguards for women before an abortion can be carried out. To protect women, the right checks and balances must be in place.
"The CQC has agreed to undertake unannounced inspections to identify the scale of this problem.
"And we will set up a special team comprising of all the necessary regulators and the department to look at how we stamp out bad practice in abortion clinics."
Lansley is understood to be preparing an urgent statement to Parliament on the issue.
The health secretary said that pre-signing forms constitutes a criminal offence and could also lead to doctors being struck off by the General Medical Council.
The news comes after an investigation by the Daily Telegraph in February, which exposed allegations that doctors at three clinics agreed to terminations based on the sex of the baby.