Greater collaboration between health services has seen 90 per cent of the district's babies being immunised on time - one of the Whanganui District Health Board's health target successes.
Babies should be immunised against diphtheria, tetanus, whooping cough, polio, hepatitis B, heamophilus influenza type B, and pneumococcal by the time they reach 8 months old.
By the age of 2, 94 per cent of Wanganui children have been immunised, including 92 per cent of Maori children and 100 per cent of Pasifika children.
The head of the WDHB immunisation steering group, Melissa Cragg, said that historically the board had found achieving the two-year target of 95 per cent of all children immunised on time to be a challenge.
"This in the most part is due to the large number of families who decline immunisation - over 5 per cent - and the transient nature of our high needs and vulnerable population -which makes the track and trace exercise to locate and immunise these children very difficult."
However, Dr Cragg said the collaborative effort made by all organisations and services involved was helping to ensure as many children as possible were immunised in the district.
She said special mention should be made of Sue Hina and Janine Spence, the immunisation team at Whanganui Regional Primary Health Organisation, and the national immunisation register administrator, Heather Steele.
"We will continue to have challenges but through the integrated approach ... solutions to these challenges will be more easily addressed," Dr Cragg said.