Accusations that swine flu was declared a pandemic under improper influence from drug firms has been denied by WHO officials.
Countries rushed to order thousands of vaccine doses when the pandemic was declared in June, but the virus proved to be relatively mild.
The Council of Europe had cast doubts in WHO's links with drug companies.
It said that major firms organised a "campaign of panic" to put pressure on the World Health Organisation (WHO) to declare a pandemic.
"Let me state clearly for the record - the influenza pandemic policies and responses recommended and taken by WHO were not improperly influenced by the pharmaceutical industry," the BBC quoted the WHO's Keiji Fukuda as telling a hearing in Strasbourg.
A number of European governments signed contracts with drug companies to buy vaccines.
Fukuda also rejected comparisons between seasonal flu and swine flu - describing them as like comparing oranges to apples.
He said the WHO response had not been perfect, but a range of experts - including some in the private sector - had been consulted and there had been safeguards to prevent a conflict of interest.
"We are under no illusions that this response was the perfect response," said Fukuda.
"But we do not wait until [these global virus outbreaks] have developed and we see that lots of people are dying. What we try and do is take preventive actions. If we are successful no-one will die, no-one will notice anything.
"We feel we should move quickly. Our purpose is to try to provide guidance, to try to reduce harm," he said.