Prof Mann was commenting on a five-year diabetes plan launched yesterday in Auckland by Health Minister Dr Jonathan Coleman.
Prof Mann, a member of a national advisory group on diabetes, said the Ministry of Health plan acknowledged it was not the response to the obesity epidemic that many critics were seeking.
But the fact it talks about dealing with pre-diabetes was an important step.
''You can prevent pre-diabetes from going on to diabetes in more than half the patients if you pick up pre-diabetes.
''It's not often you hear me say I'm pleased with a document that comes from government, but I am quite pleased with this one,'' he said.
Prof Mann was pleased the plan picked up on a worrying and unexplained increase in type 1 diabetes.
Much focus had been on type 2 diabetes, and there was less acknowledgement of an ''exponential'' increase in type 1.
The plan talks about health boards enabling eligible type 2 diabetes patients to have bariatric surgery, and Prof Mann questioned the unequal access to the procedure in different parts of the country.
''In Otago-Southland it's almost impossible to get bariatric surgery.''
''Every patient that I've referred has been turned down.''
Implementation would come down to the health boards.
''The big issue is, are the DHBs going to pick this up and run with it, or are they going to say 'sorry, we haven't got enough money'?''
Plan targets include reducing the prevalence of type 2 diabetes and reducing the number of complications and disability suffered by diabetics.
Dr Coleman said the plan provided a ''clear road map'' for tackling one of New Zealand's greatest health challenges.
''The plan places an emphasis on supporting people to manage their condition.
''We want to ensure people with diabetes or at risk of developing diabetes have the support they need to live well and access high-quality patient-centred services,'' Dr Coleman said.
