Programme predicts 14% of the vulnerable population will be hard to reach in the winter.
The report called on the United Nations to review the way humanitarian operations are funded.
Countries should donate annual "core funding" to humanitarian operations to boost "donor alerts" – appeals when a crisis happens.
The Government should produce a timetable against which the UK intends to reach the target of providing 0.7% of gross national product (GNP) towards overseas development.
"It is inevitable that an element of donor fatigue will creep in as will the temptation for UN agencies to inflate their requests knowing they are likely only to receive a fraction of what they ask for," the report said.
The committee said although refugee camps in Pakistan have been there for nearly 30 years, they had been forgotten by the international community before September 11.
The international community needs to keep an eye on the 31 "failed states" – those in a state of emergency or crisis, and there should be greater protection for international aid workers.
The committee said rather than September 11 making the humanitarian crisis worse, it had actually lessened it.
One of the members, Labour MP Tony Colman, said: "If in fact September 11 did not happen, we could have had many millions of people dying because the world community would not have responded in the way it did."Reuse content