The government is reviewing law relating to 1.42 million hectares of Maori land in bid to increase economic returns from it.

Associate Maori Affairs Minister Christopher Finlayson says a panel chaired by lawyer Matanuku Mahuika will review the Te Ture Whenua Maori Act, which covers 5 per cent of New Zealand's land.

The panel, which will report in December, also includes Tokorangi Kapea, former Brierley Investments executive Patsy Reddy and Dion Tuuta.

A Ministry of Agriculture report found that some blocks of Maori land have no governance structures and identified issues of fragmentation, uneconomic block size, difficulty with identification of owners and succession.

Mr Finlayson says 80 per cent of Maori land was under-performing for its owners, and in many cases this was because of structural issues which stemmed from the legislation.

"In particular compliance costs associated with Te Ture Whenua Maori Act and the processes of the Maori Land Court can also have flow on effects for governance.

"That is why I have commissioned a very able panel of experts to review the act and make practical recommendations for enhancing the legislation," he said.

The act was last reviewed in 2002, but most recommendations were not implemented.