About one-third of New Zealanders undertook work for an organisation and about two-thirds did unpaid work outside their home (such as helping in the neighbourhood).
In Hawke's Bay, fewer than 16 per cent of the local population volunteered, less than many other parts of the country, with Northland, the West Coast and parts of Canterbury rating higher with 21 per cent or more of their population volunteering.
Miller said it was difficult to say why Hawke's Bay had fewer volunteers per head of population.
"It's probably a little bit to do with social deprivation, that can restrict involvement, but then Northland is a deprived area so it's tricky."
He said barriers to volunteering could contribute, such as organisations not valuing or providing meaningful volunteer work.
"We need to educate organisations to make volunteer roles more volunteer friendly - to give people something they want to do rather than what the organisation wants."
He said there was too much expectation that volunteers would do unskilled work regardless of their experience.
"Yesterday I was talking to a someone who had been a teacher for 46 years and they couldn't get more than an average volunteer role - it's incredibly limiting and organisations need to start thinking creatively, rather than doing what they did 20 years ago."
People's motivation to volunteer differed depending on their age and stage of life, he said.
"For someone younger they might be thinking of career advancement, gaining experience maybe to get their first job, and a chance to mingle with other youngsters.
"For people with young kids it's about giving back say to sports clubs or groups like Scouts, and for older people it's sometimes about seeking a sense of purpose and connection with the community."
Without the efforts of these people society would look quite different, he said.
"There would be no heart, we are the heart of communities - you could not walk down the street or go to hospital or an area of low deprivation without encountering someone that wants to help - we need to recognise and value that."