The shake-up of the out-of-hours health care system in England was "shambolic" and led to longer waits and higher costs, a committee of MPs has said.
The way people obtain health advice at night has changed
New providers are spending 22% more but are not meeting key targets, the public accounts committee claimed.
Fewer than 10% of primary care trusts met targets on assessing patients within 20 minutes of an urgent call.
Most GPs opted out of the organisation of the service in 2004, and PCTs took over in 90% of cases.
Ministers said the new arrangements were already benefiting patients.
It follows a National Audit Office report which found serious shortcomings with the handover arrangements - but said patient safety had not been compromised.
PCTs had little experience of running such services and were poorly prepared for the transfer between April and December 2004, the NAO said.
Consequently many contracts were signed late or not at all.
Where external providers took over the service, contracts were not signed in two thirds of cases by September 2005.
This led to insufficient monitoring of official service standards, the NAO said.
Only a minority (15%) of PCTs could confirm that key targets on responding to emergency calls were being met.
Among other missed targets, the NAO report found only 21% of trusts could show they gave a face-to-face consultation at a patient's home within one hour for urgent cases.
About a quarter could prove they did so for less urgent cases within six hours.
NAO director of health Chris Shapcott explained that around half simply did not have the information - which made it difficult to be sure that patients' safety had not been compromised.
"The view of the PCTs and providers that we spoke to was that it was not compromised, there was no evidence of increased complaints, but what there was evidence of was some very long delays."
Although the NAO said the service was now beginning to reach a satisfactory standard, one in five patients were still not satisfied.
The report also raised concerns about the costs of the new service which rose from the Department of Health estimate of £322m to £392m in the first year.
The financial impact of this increase in cost has been considerable for PCTs, the report said.
Chairman of the public accounts committee Edward Leigh said: "The new way of providing out-of-hours medical care has so far been a costly mess that has left many sick people waiting too long for help."
Public health minister Lord Warner said officials would work with the NAO to improve the efficiency of evening and weekend cover but stressed the old system was unsustainable.
PCTs would be told to draw up action plans for improvements and offered "master classes" to ensure they grasp the changes needed, he added.
"The NAO report confirms that the NHS is on the right track towards providing quality round-the-clock GP services with high levels of patient satisfaction with the new arrangements."
Dr Hamish Meldrum of the British Medical Association agreed the old services were unsustainable - but said it was unacceptable for patients to face delays.
Better integration of services and planning was needed, he said.
Jo Webber of the NHS Confederation, which represents 90% of health service organisations, said that 80% of patients were satisfied with the service.
She added that PCTs were learning rapidly from experience gained during the first year of commissioning and that the report would help that process.