North Korean hackers have been targeting the successful digital currency in a bid to circumvent the sanctions placed on despotic regime as the dictatorship continues it nuclear weapons programme.

Lee Dong-geun, a director with South Korea's internet and security agency, said: "It is a fact that North Korea has been attacking virtual currency exchanges.

"We don't know how much North Korea has stolen so far, but we do know that the police have confirmed the regime's hacking attempts."

According to police, North Korean hackers have targeted at least four different exchanges that trade bitcoin and other digital currencies in July and August.

And experts warn that attacks are likely to continue as bitcoin's price skyrockets.

South Korea’s government has called an emergency meeting on cryptocurrency with new measures on trading expected to be announced on Friday.

Earlier this year bitcoin was hovering below $1,000 but the cryptocurrency has soared more than 1,500 per cent, crossing $17,000 for the first time last week.

The digital currency was designed to operate outside of the control of governments or banks which would appeal to the heavily sanctioned North Korea.

Experts admit it is unclear how much bitcoin and other cryptocurrencies North Korea has amassed due to the currencies’ seller anonymity.

Bryce Boland, the chief technology officer for the Asia Pacific with cybersecurity firm FireEye, said: "It's reasonable to assume some – and the value is increasing significantly at the moment.”

Bitcoins are often held in accounts with online exchanges and according to Mr Boland hackers can easily swap them into more obscure cryptocurrencies before eventually withdrawing them in traditional currencies like dollars.

He added: ”They could do those transactions very quickly ... and avoid traceability of the cash.”

Independent security researcher Ashley Shen who has been tracking three hacking groups – Lazarus, Bluenoroff and Andariel – believe they may be connected to North Korea.

Ms Shen said: “When we tracked nation-state attackers, they usually perform cyberattacks which are aimed at confidential data and intelligence.

“However recently we’ve discovered that some of the APT (Advanced Persistent Threat) groups are trying to hack financial institutions like banks and Bitcoin exchanges to gain financial profit.

“Digital currency might be easier to gain than physical currency.”

North Korea has repeatedly denied it has been involved in international attacks – but it has made no secret of its interest in bitcoin.

Last month, the elite Pyongyang University touted a lecture from a bitcoin expert as part of its cryptocurrency course.

Federico Tenga, founder of bitcoin startup, Chainside, was approached by the university, which is believed to be the breeding ground for North Korea’s hackers.

The university said: “Many excellent technical questions were asked about the inner working of bitcoin, its risks, and the measures taken to ensure security.”

Meanwhile, Priscilla Moriuchi, director of strategic threat development at CIA and Google-backed security intelligence firm, Recorded Future, said: “There should be no mistaking this course as a benevolent academic exchange; everything in North Korea is carefully evaluated and managed by the regime.

“The university was allowed to offer this course, bring in a foreign expert, and educate North Korean students because the government and senior leaders realised the value of bitcoin and cryptocurrency as a generator of funds for the regime and allowed it.”

North Korea has repeatedly been slapped with sanctions following its missile test, with the latest batch in November by the US targeting trade between China and the rogue state. 

The new measures were imposed after Donald Trump announced the rogue state was being re-listed as a “state sponsor of terror”.

The North is already subject to a raft of sanctions from the US, United Nations (UN) and the European Union.

In September the United Nations voted unanimously to step up sanctions on North Korea following the country’s sixth and most powerful nuclear test, imposing a ban on the country's textile exports and capping imports of crude oil.

It was the ninth sanctions resolution unanimously adopted by the 15-member council since 2006 over North Korea's missile and nuclear programs.