A New Zealand scientist has come up with a measuring device that literally undercuts its American rivals.

Photo: Supplied

Chris Sutton's Kibble balance is the size of a table top - compared to an American version the size of a two storey building.

In an era when much of our physical world is increasingly being defined by physics, the kilogram is the last standard measure still relying on a physical object.

That global standard "prototype kilogram" is a cylinder of platinum-iridium alloy stored by the International Bureau of Weights and Measures at Saint-Cloud, France, which countries use to calibrate their own measures.

Problem is, it's losing mass.

And even a tiny nick could suddenly change the world's perception of how much weight makes a kilogram.

So scientists are working to re-define the international system of units in terms which won't suddenly change.

"Essentially we've picked a number of fundamental constants and linked each of those to one of the key quantities," Dr Chris Sutton said.

For mass it's the Planck constant - which links the amount of energy a photon carries with the frequency of its electromagnetic wave - and there's a machine which can use that information to calculate a kilogram

"Which means it's a bit like a recipe," Dr Sutton said.

"You go into the kitchen, get all the ingredients out. Put H in one end and all the kilogram comes out the other end," he said.

"It's much more convenient if we can just follow a recipe and create a kilogram and know that it's going to be the same as other kilograms created following the same recipe".

Using the Kibble balance means New Zealand will have its own machine to do that.

Dr Sutton and his team are half way through building the New Zealand version - which is much simpler than current versions of the instrument.

Photo: Supplied / Callaghan Innovation

The team started building it two years ago and hope to have it operating next year.

Such a redefinition would allow for more accurate measurements of mass, which have potential implications in the study of many fields, from quantum mechanics to mechanical engineering.

At the moment there are four operating in the world and physicists are hoping to double that number.

It's hoped to launch the new system worldwide on 20 May 2019, which also happens to be World Metrology Day.

Top honour

In November, Mr Sutton was awarded one of the top honours in the field of metrology - the science of weights and measurements - receiving the Asia Pacific Metrology Programme Award (APMP) for his "significant contribution to the development of metrology in the Asia Pacific region."

Dr Sutton helped to establish the group in 1977, because his boss at the time did not want to go to India.

"In my naivety and enthusiasm I said, 'oh yes, we'll run this', so we offered to be the first chair of the organisation."

The Asia Pacific was the first regional group to be formed and since then others have followed, with regional groups formed from South America to Russia.

Aside from working to make the trusty kilogram trustier, he is also responsible for correcting errors in measuring distances with lasers, improving pressure measurements using pressure balances and finding a better way of comparing measurements internationally.

Measurements and Standards Laboratory director Dr Fleur Francois said the APMP Award was one of the highest honours a meteorologist can get.

"It's a tribute to his work not just as a scientist, in a 45-year career, but also for his contribution to setting up international agreements on metrology. These allow countries to recognise each other's measurements, which is very important for trade, for example," she said.