Speakers included Wanganui mayor Annette Main, deputy mayor Hamish McDouall, environmental activists Nicola Young, Rochelle Bullock and Nelson Lebo, and Mr Cresswell.
Mr Cresswell said the march coincided with the 2015 United Nations Climate Change Conference, in Paris beginning today.
The Wanganui march was one of several dozen marches to take place in centres throughout New Zealand, with many more around the world.
"The purpose was to encourage our politicians to take strong action to preserve our climate. And to let people know that we all need to get active on this issue, in our lives and politically," Mr Cresswell said.
"It's the most important issue facing society today."
Rebekah Walker said she went to the march because she wanted to "speak for the earth".
"My entire life revolves around nurturing the earth and reminding people how to connect with the roots of our survival. There are always creative solutions [to issues like climate change] and I hope to inspire others to look for them and implement them in their own homes and lives," she said.
Brenda Gregory joined the march with her daughter Sue. She said she had heard about the marches happening around New Zealand, and was very pleased one had been organised for Wanganui.
She said she was not surprised so many people had turned out for the march.
"I knew it would be a big crowd because it's such an important issue.
"I marched because I wanted to send a message to the government that we need urgent action on climate change, not just more talk."
Mrs Gregory said she would be watching to see what comes out of the Paris conference.