The Western Plains Zoo, as it was originally known, was the first open range zoo in Australia, opening to the public in 1977. But the site just outside of Dubbo was not the only location the government of the day considered.

"It could have ended up out of Parkes," Mr Mason said.

Mr Mason was the state member for Dubbo from 1965 until 1981, and was also the minister for lands when the decision was made to build an open range zoo to complement Sydney's Taronga facility. He was determined to get the zoo in his electorate.

"By that time I was the minister for lands, which put me in the box seat, so I said to the district surveyor go and see if you can find a good site. So he went and had a look and he came back with two suggestions: one out of Parkes, a good way out of Parkes, and one at Dubbo."

"It could have ended up out of Parkes but I said 'oh well, we'll build it at Dubbo'."

"I suppose it could have gone anywhere. I restricted the area, I was determined that it would be in my electorate."

"If the site at Parkes had been better I suppose I would have had to look seriously at it, but see this was an old ex-army camp and an arboretum, that ran all along the highway, so of course we added that into the site. So we had a great site, close to Dubbo, the site just spoke for itself. It made it very easy for me."

Mr Mason is proud of numerous other achievements during his time as Dubbo MP, including working with the local council of the time towards the beautification of the riverbank, and the completion of Burrendong Dam.

"One of the great things I think we did when we came to power was we really looked at the whole water system, across the whole state and we built more dams in our period of government than had ever been built in the state before," Mr Mason said.

But with the zoo, he really left his mark.

"I think it was really the making of Dubbo," he said.