The new platform should be ready by the first meeting of the Jersey Race Club at Easter, and the building will include permanent public toilets and new changing-rooms for jockeys.
Club president Robin Rumboll said that the changes would mean a big improvement to the race day experience.
Mr Rumboll said: ‘Last year there were plans for a new clubhouse and all the other facilities, but because of the delay and escalation of costs we had to rethink the proposals.
‘The new scheme has now been approved, and it is a significantly different concept.
Basically the new building will now incorporate a grandstand viewing area which will be a grass slope.
The building is a long rectangle structure and the viewing bank will be supported by it.
The building will incorporate all racing facilities including the weighing room, the jockey changing-rooms, the new Tote building and significantly larger public toilets for racegoers.
It will be a very functional building.’