The Whanganui Justice for Moko march is happening on June 27.
Whanganui co-ordinator Marilyn Kairimu wanted to stress the march was not a protest.
Marches have been organised around the country to coincide with the sentencing of Tania Shailer and David William Haerewa in the Rotorua High Court.
The couple pleaded guilty to the manslaughter of Moko Rangitoheriri, a 3-year-old in their care tortured to death over a two-month period.
Miss Kairimu said the Whanganui march was to be "respectful".
Those attending will meet at Majestic Square at 8am. The march will begin at 8.30am.
The marchers will head down Victoria Ave to the Whanganui District Court, which they will wait outside until the sentencing in Rotorua is finished.
"We will be all around there, just not in front of the doorway, because there's other things that are happening there," Miss Kairimu said.
She said the marches had been organised on behalf of Moko's family.
"Come open-minded. We're doing this for the rights of the children, of the children that have been wrongly taken from the families. For united we stand, divided we fall."
Anyone wanting to attend could head to the Whanganui Justice for Moko Facebook page for more information.
They can also contact Miss Kairimu on 020 400 30246.