"There will be microphones set up on the day, and everyone is welcome to get up and sing a song, or read a poem, or even rap.
"I've actually written a song about Covid-19 in New Zealand, but, now that we're free of it, I might have to change the lyrics to other places around the world that are still affected, like New York or Italy."
Stone said he would also perform his own version of the New Zealand national anthem, called We are NZ.
"It's something a little bit different, and there'll be four-part harmonies. The words remain the same though.
"I encourage everyone to bring their dancing shoes, guitars and singing voices, because it's time to party."
City Life Impact would now be called Maori Interdenominational City Life Impact, Stone said, with services being held in both English and Māori.
"I attended church services in France where different languages were represented, and I thought that it should be something we do here too.
"We want to be as inclusive as possible, and the concert will be a celebration."
The concert runs from midday to 2pm on Saturday at Majestic Square.
City Life Impact services are held at 10.30am on Sundays. The church is opposite the Whanganui Opera House in St Hill St.