Japan’s biggest-selling newspaper has apologised for its past use of the term “sex slaves” to describe tens of thousands of women who were forced to work in Japanese military brothels before and during the second world war.

The move by the Yomiuri Shimbun, a conservative broadsheet with a daily circulation of more than 10 million, has fuelled concern that sections of the country’s media have signed up to a government-led campaign to rewrite Japan’s wartime history and portray its actions on the Asian mainland in a more favourable light.

Revisionist attempts to portray the women as willing prostitutes hired by private brokers has soured Tokyo’s relations with South Korea, where many of the victims came from. The Japanese prime minister, Shinzo Abe, has yet to hold a bilateral summit with his counterpart in Seoul, Park Geun-hye, since he took office in December 2012.

In a statement carried in its Japanese and English-language editions, the Yomiuri said it would continue to use the phrase “so-called comfort women”, a more ambiguous wording critics say downplays the women’s plight.

Many mainstream historians and overseas media use “sex slaves” to describe as many as 200,000 women – mostly from the Korean peninsula – who were forced to work in frontline brothels until Japan’s defeat in 1945.

The Yomiuri said the “inappropriate” descriptions had appeared on numerous occasions in its English-language edition the Daily Yomiuri, now known as the Japan News, for more than a decade up to 2013. The paper said it had not come under pressure from outside to alter its editorial policy.

In September, Japan’s historical revisionists received a boost when the liberal Asahi Shimbun retracted several articles it ran in the 1990s about wartime sex slaves.

The coverage was based on the falsified testimony of Seiji Yoshida, a former soldier who claimed he had witnessed women from the South Korean island of Jeju being abducted to work in military brothels. Yoshida, who died in 2000, has been discredited by independent investigations by academics and other newspapers.

Senior Asahi staff resigned and the paper became the target of sustained attacks on its editorial credibility from conservative rivals, including the Yomiuri.

In line with claims made by leading conservative politicians that there is no evidence that the military coerced the women, the Yomiuri said the previous wording had created the mistaken impression that sexual enslavement was official wartime policy.

“The Yomiuri Shimbun apologises for having used these misleading expressions and will add a note stating that they were inappropriate to all the articles in question in our database,” the paper said in a statement printed in the Japan News on Friday.

The paper cited 97 articles published between 1992 and 2013 that used “sex slave” or “other inappropriate expressions”.

The Yomiuri, a staunch supporter of the governing Liberal Democratic party, said “sex slaves” had never been used in its Japanese edition.

“The expression ‘comfort women” was difficult to understand for non-Japanese who did not have knowledge of the subject. Therefore the Daily Yomiuri, based on an inaccurate perception and using foreign news agencies’ reports as reference, added such explanations as ‘women who were forced into sexual slavery’ that did not appear in The Yomiuri Shimbun’s original stories,” the paper said.

Abe is one of several conservative politicians who have blamed the Asahi – and overseas media coverage of the sex slave issue they claim was based on the newspaper’s falsified stories – for damaging Japan’s international reputation. But he has stopped short of revising a 1993 government statement apologising to the women.

Mainstream historians point out, however, that the Asahi’s recent retraction does not invalidate their contention that Japan’s wartime government and military were involved in coercing the women.