Northern NSW has the lowest rate of fully immunised children in the country while the Snowy Mountains has the highest rate, according to the latest data.

Northern NSW has been identified as one of the areas with the lowest immunisation rates in the country with nearly a quarter of one-year-olds not vaccinated, according to new data.

The National Health Performance Authority's latest data analysing immunisation rates over a two-year period from 2013-2015, shows Australia has recorded improvements in the percentages of children fully immunised.

In the year 2013-14, nearly 30,000 children aged one were not fully immunised, with that figure falling to 26,671 in 2014-15, the data released on Thursday says.

However, the percentage of one-year-old children fully immunised in the Brunswick Heads and surrounds was as low as 73 per cent.

Sydney's western suburb of Harris Park also rated low with a figure of 76 per cent.

The NSW Snowy Mountains has come in with the highest local area rate in the country, with 97 per cent of one-year-olds fully vaccinated, the data says.

Northern Victoria also recorded a low level of vaccinated one-year-olds with rates of 80 per cent, while Queensland's central coast levels of immunised one-year-olds was 82 per cent.

The report says 84,571 children aged one, two and five were not fully immunised in 2014-15.