The publisher of Japan's leading newspaper apologised to readers Thursday for several serious errors in its reporting, retracting an article that claimed workers abandoned their posts during the Fukushima nuclear disaster.

Asahi's publisher Tadakazu Kimura, speaking at a hastily arranged news conference, made the apology after a confidential government document cited in the daily's report was finally released to the public with no mention of a mutiny by plant workers.

"I offer profound apologies to our readers and people at Tokyo Electric Power Co. (TEPCO)," the 60-year-old publisher said.

He said he would decide whether or not to resign after enacting "revival through sweeping reform."

The article published on May 20 said 90 percent of workers at the Fukushima Dai-ichi nuclear power plant had left the complex, disobeying the plant chief's order to stay put in the worst nuclear accident since Chernobyl in 1986.

TEPCO operates the plant, located 220 kilometres (138 miles) northeast of Tokyo. A massive earthquake and tsunami crippled its cooling systems and sent reactors into meltdown in March 2011.

The daily said about 650 employees, or 90 percent of the plant's workforce, retreated to another seaside TEPCO nuclear plant 12 kilometres away when the nuclear crisis worsened a few days after the accident.

The official document released Thursday recounted the testimony of plant chief Masao Yoshida to a government investigative panel, with no trace of staff "disobeying Mr. Yoshida's order" as Asahi had claimed. Yoshida died of cancer in July last year.

Other dailies which also had access to the then confidential statement had already cast doubt on the article.

In the same news conference, Kimura also admitted a highly contentious report published 32 years ago on the topic of Japan's wartime sexual enslavement of Korean women was also false.

That report cited a Japanese writer who claimed to have witnessed the kidnapping of women on the South Korean island of Jeju for the purposes of sex slavery, which has since been discredited by independent research by rival newspapers and academics.

Asahi admitted in early August that its 1982 article on the comfort women and follow-up reports were based on a "false" statement by the witness, but Kimura's apology was the publication's first in relation to it.

"I apologise to readers for publishing the erroneous articles and being too late in making the correction," he said.

The admission of the mistake has boosted the country's conservative forces, which have insisted there was no "sex slavery" at the frontline brothels and that many of the comfort women were highly paid prostitutes.

Prime Minister Shinzo Abe told a radio talk show Thursday the comfort women report had "agonised many people and impaired Japan's reputation in the international community."

With few official records available, researchers have estimated up to 200,000 women, many from Korea but also from China, Indonesia, the Philippines and Taiwan, served Japanese soldiers in "comfort stations".