Public toilets are usually a welcome sight to anyone who has had too much to drink, but some might do a double take when they come across the ones that have just opened in a Tokyo park.

Made of special glass, the cubicles become opaque when the lock is turned, but are otherwise completely see-through, with sinks, urinals and toilet bowls in full view.

The toilets were designed by architect Shigeru Ban as part of the Tokyo Toilet Project, which is backed by The Nippon Foundation, a non-profit organization.

By installing stylish toilets in public spaces the project hopes to change the common view that such facilities are dark and dirty places.

"It would be great to see the Tokyo Toilets become a model for toilets not just in Japan but across the world," Nippon Foundation Program Director Hayato Hanaoka said.

Passers-by had mixed reactions.

"It's really cool, but it wasn't very relaxing," said 28-year-old Arisa Komori, who was visiting the park with her friend and had used the toilet. "But it's also pretty," she added with a laugh.

Some said that being able to see inside the toilets first made them feel safer about using them.

"You can see straightaway that there aren't any suspicious people lurking in the toilets, so I appreciate that I feel safer about letting my children use the toilets," said Chieri Kurokawa, 36, who lives nearby and had brought her two young sons to play in the park.

As part of the project, a total of 17 public toilets will be redesigned by renowned architects and designers, including Pritzker Prize winning Tadao Ando and Kengo Kuma.