Fairfax Media was provided with a rare glimpse into the logistics of the exhibition by NGA assistant director exhibitions and collections Adam Worrall.

Mr Worrall said the security arrangements for the 300-piece Cartier exhibition were "20 times more" than Masterpieces From Paris - which featured Van Gogh - that came to the capital in 2009-10.

The Queen of England herself loaned the gallery five pieces from her personal collection, to accompany more from the Royal Trust.

Mr Worrall said once the Queen had agreed to lending her jewellery, the other British collectors quickly came on board.

But just how did the jewellery get to Canberra?

Each piece had a security escort from the minute it left the lender or the institution until it was safely locked in the glass cases at the National Gallery. Most pieces travelled to the capital on commercial flights.

"There is a security person with them the entire time that piece is moving," Mr Worrall said.

"When it arrives at the gallery and gets locked in the safe, then the security leave. Then when we move it from the safe up into the gallery space, while we're unpacking it, while we're pinning it, until it gets installed, there is security escorting every single movement of every single piece the entire time until we lock it in the showcase. Then that work is safe and it can be signed off and everybody breathes a sigh of relief. And then we go onto the next one."

Mr Worrall said it was the expectation of what you have to provide in an exhibition of this value.

"Jewellery and paintings are very different," he said.

"If you steal a Van Gogh, you can't sell it anywhere because everyone knows that that's the Van Gogh that is missing. Whereas jewellery is very portable and easily changes hands, so there's perceived to be much greater risk around jewellery of the size of the works that has meant that security is so high."

In a career spanning three decades, Mr Worrall said the security logistics around this exhibition were "like nothing that I've dealt with".

The show has been three years in the making and does not fail to disappoint.

But the security wasn't the only challenging aspect.

"It's been a really tricky show to pull together," Mr Worrall said, as about one-third of the pieces have come from private collections.

"Traditionally you just write to lenders and they write back, and you're generally dealing with institutions that know about loaning objects to a gallery. This is a totally different ball game to most of the exhibitions that we do.

"That has been the challenging bit - how do you write to the Queen to ask for seven pieces of Cartier jewellery that are in her personal collection?"

"We got a lot of advice from people we hadn't worked with before about how do you approach people to get things from their personal collections."

Mr Worrall said the gallery wrote to the keeper of the Queen's collection who in turn spoke to the Queen.

"We got a letter back, middle of last year, from the keeper of the Queen's collection. The most amazing letter I've ever received, on the royal letterhead, explaining that they'd met with Her Majesty and Her Majesty’s dresser to work out what jewellery she will be wearing between May and September 2018, and she's really happy to say that she's loaning five of the seven works you've asked for."

Mr Worrall said the Queen was "incredibly generous" in what she loaned to the National Gallery of Australia, including pieces like the Halo tiara Catherine, Duchess of Cambridge wore on her wedding day.

When the packing boxes arrived housing the Queen's personal jewellery, inside, Mr Worrall said he was amazed to find the pieces in their original Cartier packaging.

"When you commission [jewellery like] a tiara, they actually make you the most beautiful Cartier box that perfectly supports the work inside. It articulates when you open it, so when you open the lid of the box a little flap actually lifts up the tiara a little bit, so it's facing you when you open the box and you can easily lift it out."

"That was so exciting to see that these had been so beautifully cared for that the original packing they would have been given to the original owner in still existed and travelled around the world."

The Queen's Cartier on show in Canberra also includes the Nizam of Hyderabad necklace she wore in the 1950s for the portrait that usually hangs in Parliament House, of Her Majesty pictured among touches of wattle.

The portrait is on loan to the gallery, appearing beside the necklace.

"It's the first time in 60 years that that portrait and that necklace she was wearing have actually been brought back together and displayed together since the painting was painted. Australians have seen that painting at Parliament House, it's the painting of the Queen that is on display, so to have it here in the National Gallery is great and to have it with the necklace is even more extraordinary."

Mr Worrall points to some of his favourite pieces around the exhibition - which tend to be the ones with the largest gems.

He admitted that three years ago, he was "a total non-jewellery fan". A special tour of the Cartier workshop in Paris changed that for him.

"I had no understanding of what fine jewellery was, but going through the workshop really transforms your understanding of what great jewellery is.

"I became a bit of a convert pretty quickly."

While there has been public skepticism levelled at the exhibition, Mr Worrall said the gallery was confident that the works belonged there.

"The artistic skill required to make what they make is equivalent of any great artist around the world. You can see it in the quality of the work they do."

One thing was for sure, the security measures in place meant Mr Worrall, for once, gets a sound night's sleep.

"Because of the level of security involved, I am quietly confident that this exhibition is absolutely safe when I go home at night," he said.

"Everything in the exhibition is locked behind glass, this is rare for me. I have greater concern over a big painting show where it's easier for someone to trip over and put their hand out if they fall and put it through a great Italian masterpiece or something like that. This exhibition is totally secure, I have no concern about that at all."

The Cartier exhibition is on until July 22.