In the red dirt of central Australia, what looks to be nothing more remarkable than a rusty steel cable looped across the ground is central to a global effort to monitor North Korea's budding nuclear arsenal.

This jumble of wires is actually a high-tech monitoring station designed to measure shockwaves deep within the earth.

Last September, it became one of six seismic monitoring stations across Australia and its territories that sounded the alarm when North Korea last exploded an atomic bomb underground.

As tensions spike on the Korean peninsula amid speculation that Kim Jong-un will soon test another nuclear weapon, the monitoring stations are again listening carefully. They are key to understanding the nuclear games played by a notoriously secretive regime.

The stakes could hardly be higher. US President Donald Trump has warned of pre-emptive military strikes and has dispatched a US carrier fleet to sail in nearby waters. North Korea has in recent weeks lobbed long-range missiles into the sea.

Meanwhile, at Warramunga near Tennant Creek in the North Territory, this seismic station is part of a global alert system. It's designed to detect tremors caused by nuclear tests anywhere on the planet - one of four types of technology used to detect atomic explosions.

Another station on the far-flung Cocos Islands can detect ultra-low frequency sound waves – inaudible to the human ear – that result from large explosions, while specialised equipment near Townsville measures for what scientists call the "smoking gun" particles – tiny radioactive "radionucleides" – in the atmosphere, which are blown long distances by the wind.

On the coast of Western Australia, another station is designed to detect long-range sound waves in the ocean. Other detectors are located in NSW, Tasmania and Macquarie Island.

The system has been painstakingly created over the past 20 years to support the Comprehensive Test Ban Treaty, with more than 180 nations involved globally.

The treaty aims to ban nuclear tests by any nation, anywhere, although North Korea is the only country to explode a nuclear device this century, including two tests last year.

The network requires only three stations to confirm a nuclear test, via triangulation, but 120 stations picked up the most recent test last September, providing evidence beyond doubt that North Korea was breaching UN resolutions. 

"These actions contribute to making it one of the most isolated countries in the world," said Lassina Zerbo, head of the international organisation charged with monitoring for nuclear tests, during a visit to Melbourne last week.

Dr Zerbo said the stations send data "in near-real time, with unrivalled reliability and precision", and has proved invaluable not only for detecting the North Korean nuclear tests, but also for disaster warning and scientific research.

More than 2000 nuclear tests were conducted during the Cold War, most underground, but some also in the atmosphere, underwater and in outer space.

Maralinga nuclear test site in Australia became infamous for its deadly radiation, but bombs were also exploded at the Monte Bello Islands off Western Australia.

Australia was one of the first countries to sign the test ban treaty in 1996 and now hosts 21 monitoring stations, with another under construction at Davis in Antarctica.

The aim is to build a global web of more than 330 across the world, making it impossible for anyone to carry out nuclear tests in secret.

Not that North Korea is exactly hiding its atomic ambition, boasting it will have the ability to obliterate "imperialist" America.

Ironically, the US along with North Korea is one of a handful of countries that has yet to sign the test ban, which prevents the treaty from formally becoming part of international law.