CONTRACTORS are busy blazing away on board the ex-HMAS Tobruk as preparations to sink the bulk carrier fall into place.

Diver access holes have now been cut to create swim-throughs in the vessel, allowing access to the bunks, lower deck quarters and the ship's exterior.

When she reaches the bottom of the ocean, the ex-HMAS Tobruk will be unlike any other dive site in Australia.

Regional Dive Wreck Advisory Group co-ordinator Scott Rowe said the vessel will be scuttled off the Bundaberg coast in August if all goes to plan.

Mr Rowe said it would be a major drawcard for international tourist, especially when packaged with the ex-HMAS Brisbane wreck at Mooloolaba, on the Sunshine Coast.

He said unlike the ex-HMAS Brisbane, which was a frigate, the ex-HMAS Tobruk offered larger spaces for divers to explore.

"This is a once-in-a-lifetime opportunity from a tourism perspective," Mr Rowe said.

But tourism isn't the only benefit for the Rum City.

Mr Rowe said 12 local employees were hard at work preparing the pre-scuttle stage, and two or three of them were ex-navy who had served on the ship.

He said Bundaberg businesses had supplied tools needed for the work and even the container hire was done locally.

As the time near to seeing the vessel sink, Mr Rowe said the expressions of interest were about to close for the recreational diving activities.

"It's close to closing now and anyone who has a specific interest in it should get in before Friday (tomorrow)," he said.

To submit an expression of interest, visit hpw.qld.gov.au/qtenders. Submissions close Friday, February 16 at 5pm.

Ex-HMAS Tobruk project manager Steven Hoseck said the dive site would be accessible to private divers in their own vessel through a booking system.

"Tobruk served the country for 34 years, and it's fitting for the ship to serve the rest of her time from beneath the ocean's surface, providing a unique experience for divers," Mr Hoseck said.

"She will add to the region's existing natural attractions and will support marine ecosystems in the waters of Wide Bay, which will make the dive site even more spectacular to visit."