Plans put in place to relieve the pressure on A&E units in England are not good enough, a Health Select Committee has warned.
The cross-party group have questionned how prepared the NHS would be for next winter after describing the information provided by NHS England as "confusing" and "contradictory" information about what was being done.
In the long-term, the MPs urged NHS England's medical director Prof Sir Bruce Keogh, who is leading a review of urgent and emergency care, to look at the weaknesses across the rest of the health service.
NHS is 'flying blind'
Committee chairman Stephen Dorrell said: "The system is 'flying blind' without adequate information about the nature of the demand being placed upon it."
"The committee is mindful of pressures which will build and is concerned that current plans lack sufficient urgency."
They concluded that all parts of the NHS - including social care, GPs, ambulance trusts and the 111 phone line - needed to have a plan place by the end of September to ensure they were ready for the winter peak.
The report comes after the NHS missed its four-hour waiting-time target in the first three months of this year.
The MPs also suggested ambulances could treat more patients at the scene to reduce the number of transfers to hospital, while the new 111 non-emergency phone number needed to get better at offering advice.
Urgent care boards
Earlier this year NHS England announced urgent care boards would be created to form action plans and release money to combat the difficulties being faced.
But in the evidence sessions with senior people in the health service, the MPs were left unclear whether they were voluntary or compulsory, temporary or permanent.
The MPs also highlighted differences in data they had been given about the scale of the problems, with vastly different impressions given of delayed discharges from hospital and the increases seen in attendances at A&E.
Labour's shadow health secretary Andy Burnham said A&E departments were "routinely working below safe levels" because of inadequate staffing.
"[David] Cameron must act on this report without delay if this coming winter is not to turn out even worse than the last," he added.