"Work is central to wellbeing and correlates with happiness," he said.
The new certificate, which doctors need to submit to Work and Income when a patient wants a benefit on health grounds, coincides with the abolition of the old sickness benefit.
From yesterday, people who need a benefit because of temporary physical or mental ill-health are being allocated to Jobseeker Support, a new category which also includes the unemployed. All jobseekers are required to look for work, although work obligations may be deferred for health reasons.
The new certificate turns the old one back-to-front. The previous certificate, introduced in 2010, asked first about whether a patient was in hospital or pregnant, then about their health condition, and then asked doctors to judge whether their patient could work fulltime, part-time or only plan or train for work.
The new version moves the details about hospitalisation and pregnancy to the back of the form.
Instead, the first page is a new section headed "capacity for work" which asks doctors first about their patient's "barriers to work" and, in a new question: "What accommodations, supports or services could be put in place to assist the person into suitable and open employment?"
A note at the top of the form tells doctors: "The information you provide will be used by Work and Income to help set appropriate work expectations and assist people into work."
A former doctor at Wellington's Newtown Union Health Service who represented general practitioners on an advisory panel that drew up the new policy, Dr Ben Gray, said he was "pleasantly surprised" and he was happy to sign up to the emphasis on "work is good for health".
"That is very solid science," he said.
"So the main point of the new form is to get away from being a sickness benefit form. It's to be a descriptor of what the barriers to work are."
Dr Gray, who is now a senior lecturer in general practice at Otago University, said the key to success for the new approach would be whether Work and Income used the new information from doctors to overcome those barriers by working sensitively with patients, their employers, and if necessary services such as counselling and addiction treatment.