The Newcastle-built navy supply-ship will be decommissioned at the end of July, after 34 years of service.

Seeing the ship berthed at the Port of Newcastle was a poignant moment for former shipwright John Fisher, who oversaw its construction at Carrington Slipways, from the laying of the keel in 1978, to the ship’s launch in 1980 and commissioning in 1981.

"It’s an absolute credit to the ship builder and the men and women of Newcastle who worked on it," Mr Fisher said.

About 400 people helped build the vessel at the Tomago site and dozens of local businesses were involved in its construction, Mr Fisher said.

The Tobruk was the first ship to be launched sideways and Mr Fisher can clearly remember the ‘‘spectacular’’ event on March 1, 1980.

Since its launch the 6000-tonne amphibious vessel has travelled 974,000 nautical miles and been deployed on 26 navy operations around the world.

Tobruk commanding officer Leif Maxfield said Tobruk had been a ‘‘star feature’’ and one of the busiest ships in the navy.

In its final 18 months the Tobruk was part of humanitarian missions in the Philippines and Vanuatu and a civic assistance operation in Papua Guinea.

‘‘It’s quite fitting to return [to Newcastle] as our final port,’’ Mr Maxfield said. ‘‘It’s a great way to end what has been an outstanding career for the ship.’’ 

This is Tobruk’s seventh visit to Newcastle. In 1991 it returned for a refit at the Forgacs Floating Dock, which is no longer in the harbour.

It was the first naval ship Forgacs repaired at the dock, and it was the scene of a protracted industrial dispute with the painters and dockers union, which picketed the vessel.

The dispute was eventually settled but the painters and dockers union merged into the larger manufacturing workers union soon after.

Maritime warfare officer Darren Watkins is the third sailor in his family to crew the Tobruk.

He followed in the footsteps of his uncle, who was one of the ship’s second crew in 1982.

‘‘Hearing stories about when he was in the engine room, it hasn’t changed at all in the 34 years,’’ Mr Watkins said.

‘‘Knowing that she was built in Newcastle, and we’re returning for the last trip has been really enjoyable too,’’ Mr Watkins said.

‘‘It’s also sad that the oldest ship and the most mechanically efficient ship in the fleet is being decommissioned. 

Last year the ship was awarded the Australia Cup for mechanical efficiency. 

Tobruk will be replaced by Land Helicopter Dock systems, The Canberra and The Adelaide, which the navy described at ‘‘a quantum leap in capability’’.