The vaccination programme is to be extended to younger children
The swine flu vaccination programme is to be extended to all children aged between six months and five-years-old in Northern Ireland.
The Department of Health has said it intends to begin rolling out the programme by mid-December.
The body representing GPs in Northern Ireland said the move was a surprise.
The British Medical Association in NI said it welcomed the programme, but was disappointed the health minister had not consulted GPs before announcing it.
Meanwhile, the department also said another two people from NI have died after contracting the virus.
Both were said to have underlying health problems. This brings the total number of deaths to 15.
It is possible the vaccination programme will be extended to older children in a further phase.
The vaccine will be administered to about 100,000 children by GPs.
Derry GP and Deputy Chairman of the BMA's GP Committee in NI Dr Tom Black said: "We certainly welcome the extension of the H1N1 vaccination programme to children aged up to five years old.
"However, GPs are extremely disappointed that (Health) Minister (Michael) McGimpsey did not consult with us before this announcement.
"There has been no agreement with GPs to deliver the second phase of the vaccination programme. This programme needs to move forward on a four-country negotiation basis to ensure that H1N1 vaccinations are delivered safely to patients."
A spokesperson for the Department of Health said they understood negotiations had taken place at national level and they had hoped to engage with the BMA locally once they knew which children were the next to be vaccinated.
Chief Medical Officer Dr Michael McBride said in the last seven days, levels of flu activity was highest in those under the age of four.
"We have had somewhere in the region of 500 plus admissions to hospital, and more than 130 of those have been under four years of age," added Dr McBride.
"This virus is having a disproportionate impact on young people, particularly on children under four years of age who are at greater risk of illness with swine flu."
Health Minister Michael McGimpsey said young children had "the highest rate of hospitalisation even without any underlying health conditions".
"In line with normal arrangements for vaccinating this age group, parents should expect to receive a letter from their GP once the first priority groups have been vaccinated," said Mr McGimpsey.
Those eligible for the vaccine will be contacted by their GPs
On Thursday, the minister also said there had been a positive response to vaccination from those people in the at risk groups.
He said: "So far almost 7,000 pregnant women, more than 2,100 children in special schools with severe learning disability and over 20,000 frontline health workers have been vaccinated."
BBC Northern Ireland health correspondent Marie Louise Connolly said: "According to a number of GPs contacted by the BBC, this is a positive move as a high number of patients are young children who through play can easily spread the infection to each other."
This second phase of vaccinations is expected to begin in early to mid-December once all of those who were initially deemed to be at risk have been vaccinated.
About 139,000 doses of the vaccine have been distributed to GPs in Northern Ireland by the Department of Health.
To date between 40,000 and 45,000 doses have been sent out each week, on Thursday the department said that from next week they will be able to ship 80,000 doses per week.
Parents will be contacted by their GP's surgery once the vaccine is available to them and it is anticipated that all children aged six months to five years can be vaccinated within a three to four week period.
Thirteen of the swine flu deaths occurred in Northern Ireland, while one person died in England and another in Spain.