The Marine and Coastal Area (Takitai Moana) Bill which replaces the foreshore and seabed legislation will get its first reading in Parliament this afternoon.
The government legislation is sure to pass despite only having the support of four of the five Maori Party MPs.
MP Hone Harawira has said he would not vote for it.
Normally MPs vote within party lines but Mr Harawira has acted like an independent MP with his decision to vote against legislation that is his party's core policy.
Mr Harawira has not returned NZPA's calls and the party said in a statement he would not be commenting.
When the proposals were announced in June Mr Harawira said they represented "pandering to rednecks".
The Maori Party was formed when now co-leader Tariana Turia quit Labour over its Foreshore and Seabed Act, passed in 2004 following a 2003 court ruling that raised the possibility, in some narrow instances, for Maori customary title to convert into freehold title.
Her party has fought for repeal and restoration of the ability to secure customary title to parts of the coastline, but Mr Harawira does not think it goes far enough and concerns have been raised about the ability of iwi to prove continuous use and occupation since 1840 to get the title.
Co-leader Pita Sharples said he shared some of Mr Harawira's concerns.
"We are not entirely happy with the bill, neither are the iwi leaders, neither are the general public but we've all done our best and this is definitely a move forward," Dr Sharples said.
The Maori Party has suggested it would revisit the situation in the future.
Prime Minister John Key said yesterday he was unconcerned by Mr Harawira's decision and in fact it gave him confidence that the Government got the new legislation right.
Labour will support the bill through its first reading but its leader Phil Goff said the division showed the bill would not resolve the issue.