David Sandbach, former chief executive of Telford's Princess Royal Hospital, said he was concerned about the level of personal information that will be provided by GP surgeries to the Care.data database.
The system is being set up to aid medical research and monitor NHS performance more effectively.. Information from GP records will be linked with data from hospitals.
Data passed on by GPs is due to include medical history information such as referrals for treatment and information about prescriptions.
Proposals being discussed next month could give outside bodies, including pharmaceutical companies, access to the information.
But the roll-out of the system has been delayed until September after concerns were raised about a lack of public awareness about the project.
Officials from NHS England agreed on Tuesday to the delay following two days of talks with the British Medical Association.
Mr Sandbach said that while he supported the principle of data collection to help provide statistics that can support medical advances, information should be provided in an anonymous format.
Leaflets are being sent out to the public with people automatically "opted-in" to system unless they ask to be withdrawn.
Details collected under the new system would include a patient's date of birth, full postcode, NHS number and gender, but not their name.
Mr Sandbach said: "The data should be anonymised at the GP practice. It is very, very simple. ntil they get the data anonymised, I would advise eveybody to steer clear of it.
"What they want to do is actually good. But it is the way they are going about it."
He said details such as NHS numbers and postcodes should not be handed over to protect patients and ensure medical records cannot be linked back to individuals.
A spokesman from NHS England, said: "The Health and Social Care Information Centre has been handling hospital data securely in this way for many years. The system is designed to be extremely secure, with a suite of safeguards to protect confidentiality.
"But we know not everyone will feel comfortable and we want to make sure they know they have the right to object," he added.