Children's Day celebrations at Springvale Park on Sunday are likely to attract around 4000 visitors if previous years are anything to go by.
Organiser Lynette Archer of Skip Whanganui says the day is all about families celebrating children and having fun.
"The day is run by not-for-profit organisations in Whanganui and each organisation provides a free activity for children at the park.
"Community funding enables us to provide a really good day, and there will be two bouncy castles - one for under-5s and one for older children."
The Splash Centre is offering free entry for children on Sunday and there will be demonstrations by Wanganui Boys and Girls Gym Club.
Mrs Archer said more than 20 not-for-profit agencies will be supporting the event and there will be opportunity for parents and caregivers to learn about the organisations.
This will be the 10th year that Children's Day has been held in Whanganui and Mrs Archer said the number of agencies involved and the numbers of people attending has grown steadily each year.
Children's Day is celebrated on various dates around the world and was first proclaimed by the World Conference for the Well-being of Children in 1925 and then established universally in 1954.
The celebration at Springvale Park on Sunday is from 11am until 2pm and all the events are free.