GRNZ would pay for the rebuild. The club owns the venue's other assets, including a grandstand. All sit on land leased from Whanganui District Council.
The current surface of the track will be removed and replaced in the rebuild, Frost said, in a move that was "overdue".
The investment by GRNZ will result in a track of the highest possible standard, he added.
Frost has been working with contractors and said the rebuild would begin "as soon as practical", and will take about four months.
The club has about 100 members, across a big area from Foxton to North Taranaki. It's one of six in New Zealand where betting is done, Frost said. Racing usually takes place every Friday night, with a day meeting on Wednesdays.
For GRNZ the racing is a trusted, respected and vibrant entertainment sport, but animal welfare organisation SAFE believes it is inherently dangerous and should be banned.
However, Hannan said animal welfare comes first for GRNZ.
"Commitment to animal welfare has been our foremost priority throughout the decision-making process.