Rigid data privacy rules for patient records will reduce time for clinical consultations.
Doctors have said a national record system to improve health care under the government's £2.3bn national programme for NHS IT will significantly reduce the time they spend with patients.
Practitioners who have seen secret details of government plans to put more than 50 million summaries of health records on a central "data spine" said the confidentially controls are so rigid and complex that they will lose valuable time with patients.
Doctors told colleagues at a conference organised by the British Computer Society that they would boycott the systems rather than damage the quality of care.
Details of national systems for electronic health records are contained in password-protected documents, called the output based specification, marked "commercial in confidence". They have only been disclosed to selected suppliers and health professionals.
Doctors speaking at the conference said that under the Department of Health's plans they would have to spend valuable time with patients discussing whether they wanted to withhold information from the data spine, and the risks for their health care if they did.
Doctors are particularly concerned that, to prevent unauthorised access, the system will log them out after only a few minutes of non-use. "We will end up repeatedly logging into the system instead of talking to patients," said one.
Glyn Hayes, a GP and chairman of the BCS Health Informatics Committee, told the conference that although he supported the idea of electronic patient records, he had concerns about whether the department's plans would work. "By implementing such an extensive, comprehensive and rigid IT system we will stop the system working," he said.
There was evidence of this happening in Canada, where legislation that was passed to control the confidentiality of electronic records sharply reduced doctors' contact time. The Canadian legislation mirrored much of the Department of Health's current plans, Hayes said.
"After 18 months the Act was withdrawn because it was found that 30% fewer patients were being seen by clinicians who were spending so much time trying to meet the privacy, confidentiality, security and implementation issues," he said.
Limited trials of patient record systems by the Department of Health in Dorset, Gloucester and Cornwall found that health care professionals may lose time in using new systems.
A spokesman for the Department of Health said any extra time doctors spent on patient consent would be more than offset by the system cutting clerical workloads in other areas, so doctors would have more time to spend with patients.