A Christchurch icon turns 40 today.

Orana Wildlife Park opened it's gates to the public at 10am, on this day in 1976.

Public relations manager Nathan Hawke said they're using the birthday to reflect on all the great things that have been achieved.

Mr Hawke said from day one, the drive through lion reserve was a crowd-pleaser.

"It was the only one of its kind in New Zealand, and that set the tone for the zoo if you like, in terms of providing really cool and unique animal experiences to enthuse people about wildlife."

Hawke said the Park is proud to have been operating so long.

"We really do appreciate the community's support over the years. Orana we think is an important Canterbury icon and atrcation, but it couldn't have done what it's done without the fabulous support of people coming through and visiting, and of course helping us through donating."

The park opened initially with just 28 animals, and now has more than 400 animals across 70 species.

Orana has been progressively constructed over the years on a dry, stony riverbed near Christchurch Airport.

Chief executive Lynn Anderson said the park went through hard times in the 1990s when there were financial difficulties and many unfinished projects.

The park, which is the only zoo in the country not heavily council subsidised, was able to come through that period and start to raise funds successfully.

This included $6 million for Orana's biggest-ever project, the Great Ape Centre, completed in 2015.

Brothers Fataki, aged 12, Fuzu, 7, and their half-brother Mahali, 6, arrived from Sydney's Taronga Zoo that year.

It's a privilege for the zoo to hold gorillas, one of the most endangered species, for international breeding programmes, Ms Anderson says.

"Visitors are coming in droves to see these guys and everyone who meets them will fall in love with them," she says.

They gorillas help bring in money which is used for conservation of New Zealand species.

Orana raises 100 per cent of funds for all capital developments and to date, more than $15 million has been raised to create the zoo.

Additional reporting by NZ Newswire