John Key's new billionaire boss a Shinto priest and opera singer

Former New Zealand Prime Minister John Key has a few jobs to do since leaving Parliament's front bench, including interviewing Sir Richard Branson and being an ambassador for a Japanese billionaire's sport charity.

His new philanthropic role with the International Sports Promotion Society (ISPS HANDA) was announced in February.

His boss, founder Dr Haruhisa Handa, is "not only a successful philanthropist and businessman, but he is also a Shinto priest, an operatic baritone, a visual artist specializing in traditional Japanese calligraphy, a Noh theatre actor, a specialist in Haiku poetry and an avid golfer", Forbes magazine said in 2015.

Dr Haruhisa Handa
Dr Handa performing his own kind of haka (Photosport)

Mr Key told NZME: "He does all sorts of stuff. He does opera in front of the [Sydney] Opera House ... and he supports the national singing scholar, just a huge range of things."

Mr Key had declined some job offers, but said "yes" when Dr Handa called him, NZME reports.

John Key
John Key speaks at the ISPS Handa World Super 6 Perth Golf Tournament in February (Photosport)

He joins Kiwi golf star Lydia Ko in working for the international charity, which supports golf for people with blindness and other disabilities.

"At ISPS we believe in the power of sport and its ability to change lives," Dr Handa said in a statement.

"The Rt Hon John Key and Lydia Ko perfectly represent our values, with their ability to inspire others both on and off the golf course."

As a former New Zealand Prime Minister, Mr Key can have a taxpayer-funded salary of $51,725 if he wants it.

He's also entitled to a taxpayer-funded car that gets replaced every 60,000 kilometres, as well as free nationwide travel when he "carries out public duties".

In 2016 Dr Handa was made an honorary member of the New Zealand Order of Merit for his sport-related philanthropy.