The boss behind the four-day week scheme at Kiwi trust management firm believes that wider use of the model could help to ease congestion in New Zealand's most populated city.

Perpetual Guardian chief executive says that while most of the attention has been focused on his firm, rethinking the way Kiwis work could have an impact well beyond one office.

"If you can take 20 per cent of people off the roads every day, what does that mean?" Barnes asks before moving on to other potential infrastructural benefits.

"If you have fewer people in the office at any one time, can we make smaller offices? If people work more efficiently or remotely, coming to the office less frequently, what does that mean for urban design?"

Part of the reason why the roads are so congested is that the standard working week we've inherited dictates that the working day should run from Monday to Friday between nine to five.

Barnes says that the key insight underpinning his experiment is that flexible working hours don't hinder productivity and that staff should be given greater freedom to select the times they feel are best suited to achieve their employment objectives.

If businesses are able to offer some staff members the opportunity to work to different schedules, then this would, in turn, have the knock-on effect of fewer vehicles on the road.

"If you're allowing them to work flexi-hours spread over five days, you're spreading the traffic and that has implications for infrastructure."

While the four-day week has been envisaged as working from Monday to Thursday, Barnes argues that this should also be up for debate. Some people might prefer to work on Saturday and Sunday, he argues they should be allowed to do that as long as they can still deliver what's required of them.