Whangarei defence lawyer Nick Leader said Northland courts were noticeably treating certain offences such as breaches of court orders seriously by sending people to jail in most cases.
"The difficulty with a blanket stand like that is the courts fail to take into account each person's circumstances," he said.
Another defence lawyer John Moroney also said it seemed a lot more people were being sent to jail for offences such as drink driving and driving while being disqualified.
Police policy of issuing pre charge warnings for minor offences could explain a reduction
in the number of convictions, he said.
"Unfortunately the stats for Northland involves human lives with ongoing consequences and the social costs of imprisonment are one we all have to bear."
The number of Northlanders convicted in court has fallen by a quarter since 2008, including a 20 per cent drop in the number of Maori.
However, the vast majority imprisoned last year in the region were Māori - 444 of the 590, or 75 per cent.
Labour Te Tai Tokerau MP and spokesman for Maori development Kelvin Davis said long standing Maori over-representation in the justice system - including the higher rate at which Maori are sent to prison for the same crimes - must be addressed.
"If Maori and non-Maori commit the same crime it's the Maori who's most likely to go to prison for it," he said.
Last year the Northern Advocate found Northland Maori were more than twice as likely than Pakeha to be imprisoned when convicted of assault.
In the past decade, about one in 12 Europeans convicted of a crime in Northland were imprisoned, while about one in seven Maori were. One in eight Pacific people and one in 11 people of other ethnicities were imprisoned.
"There needs to be an inquiry into unconscious bias in the justice system. There needs to be an inquiry into why Maori disproportionately are not getting alternatives to prison at the same rate others are," Mr Davis said.
"We don't know the answers to these things until someone's actually really looked at it seriously.
"How many years do we need to keep waiting?"
Justice Minister Amy Adams said tackling the issue of over-representation of Maori in the justice system was a priority and an ongoing concern.
"While there has been a significant reduction in total crime over the past five years for both Maori and non-Maori, these reductions have not been as large for Maori when compared to non-Maori. This means that Maori over-representation has not improved," she said.
Nationwide last year Maori convicted of a crime were imprisoned at a higher rate than any year since records began in 1980. More than 17 per cent received jail time, compared to 10.3 per cent of Pakeha.
Fifty-six per cent of all people imprisoned in 2016 were Maori - also the highest figure ever recorded.
"There is no one silver bullet, however we remain committed to addressing this issue and focusing on initiatives that will make a difference," Ms Adams said.
Ms Adams said the Government had implemented "a range of programmes and initiatives" which aimed to address high Maori representation in the justice system.
These include the Youth Crime Action Plan, restorative justice services with Maori values, Maori and Pacifica youth courts and iwi panels for low level offending as a form of alternative resolution.
