At 16 metres long with a head that weighs more than a tonne, erecting this piece of art at the National Gallery of Victoria (NGV) was a massive undertaking.

Xu Zhen's Eternity-Buddha in Nirvana features an enormous replica of a reclining Buddha, based on a 3D-scan of a sculpture in the Nirvana Caves of China.

The statue is covered with casts of classical sculptures from ancient Greece, Rome, the Renaissance and neo-classical periods.

Commissioned by the NGV but created by the artist in China, the components had to be brought to Australia and carefully assembled.

It took months to ship the work from China, and weeks to assemble it in the NGV foyer. ( ABC News: Stephanie Anderson )

Gallery director Tony Ellwood said the artwork had been years in the making.

"This work has taken about three years to construct, and then it's taken several months to get here, and now it's taken another two to three weeks to put together the full contemplation of this piece," he said.

"People are already scratching their heads about how we got this in here, in fact even our own staff are saying this has been a major undertaking."

And what is the significance of a giant Chinese sculpture, appearing to crawl with marble statues from Western art?

The work is meant to represent religious tolerance, by combining figures from Chinese and Western art. ( ABC News: Stephanie Anderson )

"This work is really meant to represent religious tolerance," Mr Ellwood said.

"It's talking about the Buddhist figure and the other figures climbing across it that are all representing different kinds of faith.

"So it's about this idea of multi-faith, harmony, tolerance in what can often be a turbulent world today.

Installation a nerve-wracking process

Life-size classical sculptures are lowered by crane onto the massive Buddha. ( ABC News: Stephanie Anderson )

Senior curator Simon Maidment admitted to a certain degree of nerves, watching the specialist team from China install the work with the help of high-ropes gear and a crane.

"The head alone weighs 1.3 tonnes," he said.

"It is very delicate, although it's large."

The installation process usually happens behind closed doors, and the presence of the public and the media added additional tension.

A team of six workers was brought over from China to assemble the arwork in situ. ( ABC News: Stephanie Anderson )

"It's a very nerve-wracking process because it's so exacting," Mr Maidment said.

"This building was designed for art that was a great deal smaller than this. It has been a complex technical task, but one we hope is totally seamless."

The work was commissioned by the NGV as part of its Triennial exhibition of contemporary international works, which will run from December 15 until April.