A claim that the new swine flu helpline and website should have been launched earlier has been dismissed by ministers.
The government is facing criticism because the National Pandemic Flu Service was not set up by April as planned.
There have also been concerns about the quality of advice offered to those at more risk from the disease, such as pregnant women.
But health minister Gillian Merron said: “To say that the National Pandemic Flu Service has been delayed, or that it should have been introduced sooner, is untrue. The service was set up at the request of GPs and the NHS and has been welcomed by them.
“Launching the service could only be done at the point where we moved from local outbreaks of swine flu to significant levels of infection across the country.”
In the past seven days more than 100,000 people in the UK are estimated to have caught the bug, continuing the acceleration of recent weeks.
Ms Merron said the service was activated when the number of primary care trusts reporting exceptional levels of activity dealing with swine flu jumped to 110.
Meanwhile, health secretary Andy Burnham told the Observer that people should be comforted that the government’s response was well planned, warning that public panic would only put extra pressure on the NHS.