Six people have died during an influenza outbreak at a nursing home in Tasmania's northwest, the state's public health department has confirmed.

The department said there had been flu outbreaks in 21 nursing homes across the state and nine were still being monitored.

In a statement, director of public health Mark Veitch said it "was a sad event for the families affected, but can occur among frail people during an influenza season".

Those who died were all residents at the Strathdevon aged care facility in Latrobe, near Devonport.

The 37-room home is run by Uniting Agewell, an organisation of the Australian United Church.

The deaths came after it was confirmed seven elderly residents at St John's Retirement Village in Wangaratta, in Victoria, died during an influenza outbreak.

The ABC has been approached by a concerned family member alleging that the residents passed away in a week "due to the outbreak being rapidly out of control".

She said her father had been diagnosed with flu, and she and her family were advised not to visit for two weeks in August.

"It is very much true the home was in complete lockdown for two weeks," she said.

The patient's daughter said she was told on the phone her father was on antibiotics, but another resident told her he was on the list for the doctor to see.

A Government spokesman said the six deaths were over the last two weeks of August.

He said the home was not in complete lockdown, but visitors were discouraged, to avoid spreading the virus.

Uniting Agewell issued a statement on Saturday saying there had been "an influenza A outbreak at its Strathdevon aged care facility ... from August 9 to 30, with the outbreak cleared on 30 August 2017".

It also confirmed the six deaths.

"All precautions to prevent an outbreak ahead of the flu season were taken, with 95 per cent of Strathdevon's 37 residents receiving a flu vaccination," it said in the statement. "All staff were offered the free vaccine, with a large number of them being immunised. "Unfortunately, despite these precautions, 31 residents were affected during the outbreak period. "All appropriate care was provided, with nine residents admitted to hospital for further treatment. "Staff did everything possible to contain and minimise the outbreak and followed all protocols, working closely with Public Health Tasmania and managing according to state Department of Heath infection control guidelines."

The nursing home operators say there was a flu outbreak in August. ( Supplied: agedcareguide.com.au )

Dr Veitch said elderly people, especially those who had chronic medical conditions, were susceptible to the virus.

"For this reason, public health services wrote to all nursing homes in Tasmania earlier this year reminding them to prepare for the influenza season," he said.

Chief executive of Tasmania's Council on Ageing Sue Leitch said although the outbreak itself was not surprising in the middle of the flu season, the outcome was concerning.

"It's a predictable type of event that could be avoided or minimised if people [are] proactive," she said.

Ms Leitch said those in contact with elderly people should ensure they take preventative measures against influenza.

"It is a relatively simple thing to try and minimise, by vaccination and hand hygiene," she said.

Concern over decreasing flu vaccination rates

Ms Leitch said it was worrying that flu vaccination rates among adults were decreasing.

"If we have less people vaccinated in the community then flus are more likely to spread more rapidly," she said, adding it was especially important that those working with older people were vaccinated.

"I think they certainly should be encouraged very firmly by organisations that either employ them or have them as volunteers," she said.

"You can get be vaccinated by a nurse, you can be vaccinated by a doctor, you can be vaccinated at your local pharmacy, it's not as if it's something that's difficult to achieve these days."

Dr Veitch said there had been more than 1,500 confirmed influenza cases in Tasmania so far this year.

"The influenza season in Tasmania this year has been moderately severe," he said.

"Tasmanians are reminded to stay away from schools, work and health and aged care facilities if they are unwell."

More can be done, researcher says

Robert Booy from the University of Sydney has researched the handling of flu outbreaks by Australian aged care facilities.

He told ABC's AM program he believed nursing and retirement homes could do more to prevent and control outbreaks of the virus.

"Australian nursing homes are under pressure," he said.

"They have limited numbers of registered nurses on call in any one shift, sometime it's only one and that makes it very hard for a registered nurse to go around and recognise the sometimes subtle symptoms of flu."

Professor Booy said declining rates of vaccination might be due to a relatively low rate of success.

"People worry that the vaccine doesn't work perfectly and they're right," he said.

"It's maybe 40 or 50 or 60 per cent effective but it's better than anything else we've got."