The rules have changed since then and, since February 27, 2001, New Zealanders had to gain a permanent visa to access services they previously got automatically, such as social security and student loans.
Mr Hamer said he worked in Australia for Te Puni Kokiri in 2006 and produced a report for it on Maori in Australia. He told a select committee that he had not appreciated then how difficult it was to get a permanent visa for people who arrived after the new rules in 2001.
"If you arrived before that date you can just apply for citizenship straight away, $150, sing Advance Australia Fair and you're there. If you arrive after that date you have to first get a permanent visa, ideally be under 45 and have skills on a list required by the Department of Immigration.
"Your application process will cost you thousands of dollars," he said. A medical examination was needed even though New Zealanders were eligible for Medicare and success was by no means certain.
"A lot of New Zealanders clearly don't even bother trying whereas they may well have the skills to get [a permanent visa], they either think they don't need it because they are never going to rely on welfare or they just can't afford it."
As part of his current studies for a PhD at Monash University, Melbourne, Mr Hamer last year surveyed 900 Maori living in Australia.
Of those, 538 had arrived after February 27, 2001, and only nine had become Australian citizens.
All but two had become citizens because they had lived in Australia in earlier periods of their lives.
Committee chairman Tau Henare said he hoped the issue of diminished rights in Australia would be taken up by the Maori Affairs committee in the next Parliament.