The Fiji Court of Appeal has ruled that all 99-year leases on native land outside urban areas are illegal.
Radio Fiji says this means that the court has declared all such leases null and void.
The legal challenge was brought by a landowning unit in Serua province whose land was leased by the Native Land Trust Board to the government for 25 years to plant mahogany.
In 1974 the NLTB cancelled the old lease and issued a new one for 99 years over the same piece of land.
The Fiji Court of Appeal has ruled that the Native Land Trust Board acted illegally because it can issue leases for a maximum of only 50 years for such land.
The landmark ruling is expected to have widespread implications on leases granted by the NLTB for mahogany plantations and also the site of the Monasavu hydro plant.