A meth importer jailed for her role in the enormous Ninety Mile Beach meth racket has had years slashed from her jail sentence.

Selaima Fakaosilea, a close relative of the late All Black winger Jonah Lomu, denied importing methamphetamine and participating in an organised criminal group.

Selaima Fakaosilea took her case to the Court of Appeal after she was jailed in relation to a massive meth importation. (Photo / NZME)

The half-tonne methamphetamine conspiracy was discovered in June 2016 when police found drugs in a campervan at Totara North, and more buried in sand dunes.

Fakaosilea was found guilty in 2019, and sentenced to 12-and-a-half years in jail.

Fakaosilea appealed against the sentence and conviction and the appeal was heard in Auckland.

Her lawyer Greg Bradford said the gigantic Northland meth stash was already "imported" by the time Fakaosilea got involved.

In a newly released judgment, the Court of Appeal upheld Fakaosilea's convictions but cut her prison sentence.

The previous sentence for drug importation offending was quashed and a new sentence of nine-and-a-half years was imposed.

The minimum period of imprisonment (MPI) was also cut, from seven years to five years and four months.

Her sentence for organised criminal group offending remains, but she can still serve it at the same time as she serves the sentence for importing drugs.

"Fakaosilea's importation offending was vastly more serious than her criminal group offending," the appeal court said in its new judgment.

"However, the criminal group offending preceded the importation in time."

Bradford said his client first assisted the drug conspiracy in early June of 2016, well after the "motherboat" bringing meth arrived.

Bradford previously told the Court of Appeal his client's jail term, and her minimum imprisonment period of seven years, were excessive.

"It was a crushing sentence, in any event."

The 501kg meth haul is one of the largest intercepted in New Zealand history.