The Swedish retail chain Ikea used political prisoners in East Germany as ''slave labour'' to make furniture, secret police records indicate.

The Sydney Morning Herald reported the German television company WDR dug up records from the Stasi, the former Communist regime's secret police, showing that Ikea developed strong links in East Germany in the 1970s, opening several manufacturing facilities, including one that used political prisoners to construct sofas.

Ikea reportedly had a factory in Waldheim, and it stood next to a prison and inmates were used as unpaid labour. Jails in East Germany housed significant numbers of political prisoners, possibly at least 20 percent of the entire prison population, according to the reports.

Quoted in a Stasi file, Ingvar Kamprad, Ikea's founder, said he had no official knowledge of the use of prison labour.

Hans Otto Klare, who was sent to Waldheim prison for trying to escape to West Germany, described conditions in the factory.

''Our labour team lived on the upper floor of the factory with the windows covered,'' he told WDR about his time making hinges and other components for Ikea furniture.

''The machines were on the lower floor and you had little rest. On the factory floor you had no proper seating, no ear protection, no gloves. Conditions were even more primitive there than in the rest of the German Democratic Republic. It was slave labour.''

Another former prisoner said he recognised some of the parts he had made when he shopped in Ikea after the fall of communism.

In the WDR documentary, Sabine Nold, an Ikea spokeswoman, made no comment other than to say business practices had changed over the past 25 years. An Ikea statement issued later said the company had no knowledge of the use of prison labour, but was sorry if it had occurred.

Kamprad founded Ikea in 1943, when he was 17. In 1994, it was disclosed that he had briefly joined Sweden's pro-fascist New Swedish Movement in 1942.

A new book by Elisabeth Asbrink, a Swedish journalist, reports that Sweden's secret service opened a file on Kamprad due to his perceived far-right leanings.