Christchurch's $20 million Margaret Mahy Playground is continuing to cost taxpayers, thanks to an extra security guard to watch children using a new slide.

The agency in charge of the city's anchor projects, Ōtākaro Limited, is spending $500 a day these school holidays on a guard to make sure children don't hurt themselves on the slide, which has become known among residents as the tower of terror.

The fear is that children climbing up the outside of the 8m-high tower, which takes children to the top of the corkscrew slide, will accidentally fall and hurt themselves.

It was closed soon after opening in June but re-opened last Friday, complete with a guard.

A parent at the playground, Tim Kotuku, said it was up to parents to keep an eye on their children and make sure they didn't endanger themselves.

"I think it's a great adventure, looks like lots of fun. It may have been not thought out very well, it looks a wee bit dangerous on the outside of it, but if they maintain some security or something it will be fine."

Photo: RNZ/ Conan Young

Joy, who didn't want her last name used, said when her two grandchildren heard the slide had re-opened, she had to make a special detour to the playground.

"I warned them there might be long queues but they said 'it doesn't matter, we'll wait'... There's so much here for them all and they can spend so long, they really enjoy it.

"[It's] a wonderful place and we're very lucky in Christchurch to have it."

An Ōtākaro spokesperson said it was talking to the manufacturer of the equipment to come up with a way to prevent children climbing on the outside of the tower.