The Department of Health has pledged no repeat of last year's flu vaccine shortage which delayed the annual immunisation programme.
The vaccine gives 12 months protection
Hundreds of thousands of doses have already been delivered to doctors in Northern Ireland.
The free jab is available to over 65s, people with health problems and, for the first time, carers are eligible.
A major advertising campaign, Catch the vaccine, not the flu, has been launched by the department.
Dr Andrew McCormick from the Department of Health and Social Services said flu was a potentially serious illness.
"It can kill. I hope that everyone who receives an invitation from their GP to be immunised will respond positively to it.
"I would also like to assure the public that medical expert advice is, that the vaccine will not give anyone the flu. I urge everyone, therefore, who is entitled, to contact their GP practices about an appointment."
Flu is highly infectious. A sneeze can carry the flu virus and, travelling at 80 miles per hour, reach distances of up to 30 feet away.
Touching objects such as toys that have been coughed or sneezed on can also pass on flu.
Those most at risk from flu include the over-65s, as well as people under 65 who suffer from chronic heart or chest conditions, asthma, diabetes or kidney disease.
It also includes those who have lower immunity due to disease or treatment with steroids or cancer therapy, or those who have any other serious medical condition.
Dr Lorraine Doherty, senior medical officer at the Department of Health, said: "This year for the first time people who are carers, are included in the programme, entitled to be immunised free of charge.
"I would therefore urge all those who regard themselves as the main carer of a physically disabled or elderly person, to make an appointment with their GP in the next few weeks with a view to getting the flu vaccine."
The jab should not be given to people who have a serious allergy to hens' eggs, or who have ever had a serious allergic reaction the flu vaccine in the past.