Mabel crowned the crane "Sparkles" after winning a colouring competition run by City of Newcastle in collaboration with the head contractor on the site, Hansen Yuncken.

In her entry, Mabel said that she chose the name "because it is cute and girls can build things too".

Decked out in a sparkly dress and a hard hat, Mabel met Sparkles on the building site of the $53-million expansion.

The crane, which was bearing a flag with its new name, dropped from its height of 33-metre to hand deliver an iPad to Mabel, a prize for her prize-winning name.

Newcastle City Council lord mayor Nuatali Nelmes tried to contextualise the mammoth task Sparkles would undertake for Mabel.

"Sparkles will move the same weight as around 50 elephants in reinforcing mesh for the concrete floors, beams, columns and walls," Cr Nelmes said.

"It will also lift around 75 hippos worth of structural steel, and 3000 square metres of roof sheeting, which is as big as around 300,000 ice blocks laid out next to each other."

The gallery's space limitations meant that only 1 per cent of its $130-million collection could be displayed at a time.

"As we reopen gallery by gallery, we'll be able to celebrate all parts of our gallery that no one has seen before," Cr Nelmes said.

The expansion is due to be completed sometime next year.