Up to 150 people from the Labour, Green and Mana parties, the NZEI, CTU and Service and Food Workers union gathered at Parliament.
Children from Kelburn Normal School's rock band and choir sang.
Ms Turei said it was unacceptable that 270,000 children in New Zealand were living in poverty.
"New Zealand should be a great place to grow up. But thousands of kids don't have the same opportunity that other children have to enjoy a good life and a fair future because their lives are hampered by poverty."
Labour's social welfare spokeswoman Jacinda Ardern said there is political will on ending child poverty.
"Unfortunately there is a complete absence of political will on the part of this Government and I use those words strongly, because you cannot deny the facts."
Child health researcher Dr Nikki Turner said as a GP she had seen a lot of sick children as a result of poverty.
"Our hospitals got busier, our children did worse in their schooling, and our children's emotional outcomes got worse because of poverty.
"Economics and income matters."
She said she supported the transformation of the in-work tax credit to a child payment for low-income families.
Manager of Every Child Counts, Deborah Morris-Travers, said child poverty was a problem for all New Zealanders.
"We see up and down the country the impacts of child poverty, and our research shows that at least $6 billion dollars is spent on picking up the pieces," she said.
