Almost a third of nurses will refuse the offer of immunisation against swine flu because they have fears about the vaccine's safety, according to a new survey.

The initial response from frontline health staff, one of the government's priority groups for vaccination this autumn, was dismissed by the Department of Health, however, as irresponsible and ill-informed.

The apparent reluctance to be among the first to receive the new vaccine emerged in a survey of 1,500 nurses carried out by the weekly Nursing Times. Overall, 30% of respondents to the magazine's online questionnaire replied 'no' when asked if they would seek to be immunised when the vaccine became available; only 37% said 'yes', while a further 33% remained answered 'maybe'.

The opinion poll, released less than a week after the health department revealed its timetable for immunisation, appears to reflect anxieties about receiving a vaccine not yet licensed for public use. That approval is expected to be given by the European Medicines Agency by the end of September or early October.

Of those who said they would not get vaccinated, 60% told Nursing Times that their reluctance was due to concerns about the safety of the vaccine. A further 31% of respondents said they did not consider the risks to their health from swine flu to be great enough; 9% thought they would not be able to take the time out of work to be immunised.

One respondent told the magazine: "I have had the seasonal flu vaccination three times and on each occasion was very poorly for several days afterwards. It can give you flu-like symptoms, which in my case were bad enough to put me in my bed."

But the health department said there were many misconceptions that needed to be addressed. Professor David Salisbury, the Department of Health's director of immunisation, said it was unfortunate that nurses could "knowingly leave themselves at risk".

He added: "They have a duty to themselves, they are at risk. They have a duty to their patients not to infect their patients and they have a duty to their families. I think you solve those responsibilities by being vaccinated.

"The evidence that we've had is sufficient to persuade the regulators that these are vaccines that will be licensed."

The Royal College of Nursing also supported the drive to immunisation. Dr Peter Carter, the college's chief executive, said: "The NHS Occupational Health Service and other community health services must ensure that getting vaccinated is as simple a process as possible. Health staff and patients suffer when nurses are off sick, so it is important that nurses do all they can to prevent themselves becoming ill."

Christine Beasley, chief nursing officer at the Department of Health, said: "Frontline nurses will be absolutely crucial in the height of a pandemic – without them, patient care will suffer, and the NHS will be stretched. Getting the swine flu vaccine will protect nurses and their patients. That's why we're offering frontline nurses the vaccine as a top priority. As well as protecting them, it will reduce the transmission of the virus to vulnerable patients."