By Emma Batha

LONDON, July 6 (Thomson Reuters Foundation) - North Korea has sent hundreds of workers to labour as "state-sponsored slaves" in EU nations as Pyongyang seeks to circumvent international sanctions aimed at starving it of money over its nuclear weapons programme, rights campaigners said on Wednesday.

North Korean labourers commonly work 10-12 hour shifts, six days a week, but up to 90 percent of their pay is sent back to the hermit state, according to the European Alliance for Human Rights in North Korea (EAHRNK).

Most are working in Polish shipyards, construction sites and farms. North Koreans are also employed in leisure and clothing firms in Malta, and have worked in other EU countries, it said.

The North Korean embassy in Warsaw denied workers were deprived of pay.

"This is all nonsense," said an official, declining to give his name. "Nobody is taking (their salaries), they work and make money for themselves."

But campaigners say North Korean leader Kim Jong-un's regime is using overseas labour to earn much needed foreign currency to offset the impact of U.N. sanctions, which were expanded in March after a nuclear test on Jan. 6 and a Feb. 7 rocket launch.

EAHRNK director Michael Glendinning said Pyongyang was "in full control and benefiting hugely".

A U.N. report last year estimated there were over 50,000 North Koreans working abroad, earning the state $1.2 billion to $2.3 billion annually, although some experts question these figures.

Most are labouring in Russia and China. Others are working in African countries and on construction sites in the Middle East, including in Qatar which is preparing to host the 2022 World Cup.

But EU countries are more attractive for North Korea because wages are higher, Glendinning said.

FAMILIES HELD "HOSTAGE"

The conditions faced by North Korean workers in Poland will be revealed in a report due to be published on Wednesday by LeidenAsiaCentre in the Netherlands.

Researchers used testimonies from North Korean labourers in and outside the EU, field research in Poland and data from governments and other sources to compile the study.

Earlier this year, LeidenAsiaCentre detailed the case of a North Korean welder who died from 95 percent burns in an accident at a Polish shipyard in 2014. Investigations showed the clothing supplied to him by his Polish employers was flammable.

Campaigners say the welder had been working over 70 hours a week without proper remuneration.

North Koreans do not have proper contracts or payslips, must surrender their passports and face restrictions in their movements, Glendinning said. They are also kept under surveillance and have to participate in ideological study sessions.

"What we're seeing is a mini-Pyongyang being exported. They are literally sending their human rights abuses to the EU and we're tolerating it," he added.

Poland issued 2,783 work permits for North Koreans between 2008 and 2015, according to the LeidenAsiaCentre which has linked 32 Polish companies to their employment.

Glendinning said Poland stopped issuing new visas for North Korean workers this year.

Campaigners say North Koreans are vetted closely before being sent overseas to minimise the risk of defection.

"They only select workers who are married and have children - hostage-taking essentially," Glendinning said.

"If they were to defect the family would likely face some kind of punishment in a political prison camp, a re-education camp or - in extreme cases - execution."

There has been one defection in Poland and possibly a few elsewhere, he said.

A recent documentary by Vice News shows footage of North Korean labourers in Polish shipyards and on construction sites, but workers approached by the filmmakers declined to talk.

One North Korean who escaped while working in Russia told them his family had been "destroyed" after his defection.

Campaigners do not want North Koreans deported to non-EU countries where conditions could be worse, but say firms must ensure they enjoy the same rights and pay as other workers.

The 2016 Global Slavery Index estimates almost 46 million people are living as slaves globally. North Korea ranks worst for prevalence, with one in 20 people thought to be in some form of modern slavery. (Additional reporting by Magda Mis. Editing by Katie Nguyen.; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, which covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit news.trust.org to see more stories.)

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