Rising from the rubble of what was once the Imperial Hotel, building one of the multi-million dollar development has reached its full height of three stories.

Joshua Eldridge, a director with managing agents Eldridge First National Real Estate, said builders were about to pour concrete for the roof of the complex.

Scaffolding will soon move from building one to where buildings two and three will be constructed under the one roof.

Stage one of The Mill development will contain 54 apartments, including penthouses, and nine ground-floor retail units.

He said more than half the apartments in stage one had been either sold or were under offer.

It is expected that owners will start moving in by late next year.

In all, there will be six multi-storey buildings containing 97 apartments.

The old flour mill, which is approaching its 125th anniversary, will contain a tavern and a restaurant.

Mr Eldridge said negotiations were under way with potential tenants for the retail sites in The Mill.

"We are negotiating with certain parties at the moment on lease terms, but we would also welcome hearing from anyone who would want to be a part of the precinct," Mr Eldridge said.

"I think it (The Mill) will be a real eye-opener for Wagga.

"It will be a retail hub for the region."