Perpetual Guardian has permanently signed on for a four-day working week.

It was introduced as a trial in March, and has been proved a success with research showing productivity levels remain intact, and job satisfaction has improved.

Employees who opt into the four-day week are eligible for a weekly rest day provided they finish their work and get paid their usual salary.

Founder Andrew Barnes told Mike Hosking he is encouraging other businesses to give it a go.

"It is about getting the maximum from your employees and in return giving them better flexibility about how they work."

LISTEN ABOVE AS ANDREW BARNES SPEAKS TO MIKE HOSKING