The Brisbane Race Club has confirmed plans for the world's largest infield stabling complex of 400 boxes to be built at Eagle Farm racetrack.

The BRC's general manger of property, Jeff Kahler, said the boxes would provide first-class facilities designed to attract the state's top trainers.

"Many major training centres around the world have stables on course but Eagle Farm will be the first to position them as a hub infield," Kahler said.

"The stabling complex will be world-class with CCTV security, rooftop viewing platforms for trainers, BBQ hospitality areas, private office suites and an ultra-modern waste collection service.

"There will be 20 blocks of stables each with 20 boxes for the one trainer.

"The stable complexes will not be shared as we aim to get the bigger trainers here. It won't be for someone with one or two horses."

The Eagle Farm course proper, which was closed in August last year for reconstruction, has already been dug up and the turf relaid with hybrid kikuyu grass.

Preliminary work on the construction of two tunnels began on Wednesday and is scheduled to be completed in time for the track's reopening in May next year.

Kahler said the $37 million infield expansion would also include 1000 car spaces for BRC members and the general public and would be linked to the main entrance via a tunnel.

The $1.2 billion renovation of Eagle Farm is being partly funded through a deal with the developer Mirvac which will build major residential, commercial and business centres at the racecourse.

Eagle Farm will be shut as a training centre from Saturday with all horses to be worked across the road at Doomben.

It is scheduled to be reopened as a horseshoe-shaped training track in November and then as a full training venue in February.

"There will be some short-term pain for Eagle Farm trainers but the long-term benefits will be great," Kahler said.