Four of the infected people are from the northern provinces of Samsun, Kastamonu and Corum, and the fifth is in the eastern province of Van, where earlier cases were also discovered.
In Istanbul, 21 people are reportedly in hospital amid fears they have contracted the virus.
Australia's Department of Foreign Affairs (DFAT) has updated its travel advice for Turkey due to the outbreak, telling Australians living in Turkey to seek medical advice about accessing anti-viral medication.
A team of experts from the World Health Organisation (WHO) have headed for the worst-hit regions in Turkey's east to assess the government's response and look for any signs of the much-feared human-to-human transmission of the virus.
Of those infected, a brother and sister from eastern Turkey died last week, becoming the first human victims of bird flu outside Southeast Asia and China, where the disease has killed more than 70 people since 2003.
The cases in Ankara, situated about 1,000 kilometres from the region where the brother and sister died, mark the further westward spread of the disease.
A senior WHO scientist said the outbreak in Turkey did not indicate an increased risk for humans and blamed the spread on insufficient health controls in the vast country.
"It seems that the epidemic has been spreading among animals in Turkey for much longer than believed," the WHO's Klaus Stoehr told German radio.
As emergency culls continued and more bans were imposed on the sale and movement of fowl, people in remote regions in the impoverished, mainly Kurdish, east handled the crisis with their own methods.
In the village of Telceker, on the border with Iran, people were seen dumping dead chickens into a stream or burying them in plastic bags.
"Sometimes the dogs unearth the chickens and then the crows come to eat them," said 12-year-old Murat Ozer.
His neighbor, Gogey, put her last surviving hen in a plastic bag and buried it in a pit, complaining that no health or veterinary official had so far visited the village where poultry continue to perish.
Newspapers splashed pictures of children tossing dead chickens in the air and cleaning slaughtered birds with their bare hands at poultry bazaars, officially banned in the east.
With many people in the region illiterate and not speaking Turkish, efforts to raise their awareness are likely to produce less than the desired impact.
The two boys hospitalised in Ankara, aged two and five, were believed to have touched gloves used by their father to carry to the authorities two wild ducks dead from bird flu he had found earlier this week in a reservoir outside their hometown of Beypazari, doctors said.
The third patient, a 60-year-old man from an Ankara suburb, was infected after coming in close contact with chicken he bred.
The three were reported well, with the boys showing no sign of illness yet.
The new cases at the university hospital in Van, which treats the majority of people suspected of being infected, were identified as a girl and a boy, aged nine and three.
Two others, a five-year-old boy and an eight-year-old girl, have already been confirmed as H5N1 carriers in the same hospital, where some 40 people are currently undergoing treatment.
Health Minister Recep Akdag, accompanying the WHO team to the east, said there was no indication so far to suggest the disease is being transmitted between humans, a possibility scientists fear may spark a deadly global pandemic.
As dozens of panicked people rushed to hospitals across the country, the presence of the virus among winged animals was also confirmed in two more regions in western Turkey.
The westernmost point where bird flu has been found since it resurfaced in Turkey last month is the province of Bursa, about 240 kilometers from Istanbul.
In October, a first outbreak of bird flu in a region close to Bursa was successfully contained.
Syria, Turkey's southern neighbor, announced it was clear of the virus, with an official denying rumors that a man had died from the disease near the border with Turkey.
"There is no case of bird flu in Syria. All reports of deaths from this illness are rumours," said health ministry official Mahmud Karim, adding that a man died recently in the northwest of the country from "pulmonary illness".
Russia said it was planning to send several health experts to help Turkey "as soon as possible" in response to a WHO request.