A key plank of the £6.8bn NHS IT upgrade project in England has come under attack from MPs.
The NHS IT project is costing £6.8bn
The Health Committee said there was a "worrying lack of progress" and raised concerns about the security of patients' electronic records.
But the MPs also said the system - an online database of 50 million medical records to be accessed across the NHS - had huge potential to improve care.
The government said the project was being implemented carefully.
But Liberal Democrat Health Spokesperson, Sandra Gidley MP said: "This ambitious project has suffered from a lack of consistent direction.
"Confidence in the system will not be boosted by the government's woeful record at handling large scale IT projects."
Meanwhile the Public Accounts Committee has criticised another aspect of the NHS.
It said the NHS was "paying lip service" to a government programme intended to boost quality and safety after high-profile scandals such as the Harold Shipman killings.
The MPs criticised PCTs, GPs and NHS contractors for poor communication and compliance with national systems for reporting clinical incidents.
For example, it found only 4% of GPs routinely reported incidents to the National Patient Safety Agency.
But the criticism of the NHS IT project - the biggest civilian programme of its kind in the world - is just the latest in a long line of negative reports.
The National Audit Office recently warned about delays and value for money.
The e-records system is part of a programme, run by a government agency called NHS Connecting for Health, aimed at linking more than 30,000 GPs to nearly 300 hospitals by 2014.
'Lack of clarity'
The new systems include an online booking system, e-prescriptions and fast computer network links between NHS organisations as well as the centralised e-records system.
The e-records system consists of two parts - the summary care record (SCR) and the local detailed care record (DCR).
The SCR will contain basic information - such as current medication, allergies and long-term conditions - and will be shared by health professionals across England unless patients object.
Any details they want held back will remain on their full patient record - the DCR - in their local area.
The cross-party group of MPs said they found "it difficult to clarify exactly what information will be contained in the SCR and what the primary uses of the record will be".
They also said maintaining its security - with different members of staff having different access authority - presented a "significant challenge" despite the controls and audit systems put in place.
They said the project had been poorly communicated to patients and that delays to the system - some parts of it are two years behind schedule - meant progress had been slow.
The MPs said Connecting for Health and the government had to make more effort to get doctors and local NHS staff on board.
Committee chairman Kevin Barron, a Labour MP, said: "We still have some way to go before patients and the profession can see tangible benefits of the new system."
And Joyce Robins, of the Patient Concern group, said e-records had been communicated to the public like a "sales pitch".
Dr Vivienne Nathanson, of the British Medical Association, said: "Public and professional confidence in the programme is low and its credibility is at stake."
A spokeswoman for the Department of Health, which was responding for NHS Connecting for Health, said e-records were about improving care and that it would consider the recommendations of the committee.
"NHS Connecting for Health is continuing with the careful and considered introduction of the summary care record in a small number of early adopter PCTs."