TOKYO - JAPANESE pop diva Kumi Koda has apologised after saying women over 35 had 'rotten' fluid in their wombs, sparking a furore that led a cosmetics maker to suspend advertisements featuring her.

'I sincerely and deeply apologise for offending people with my remark,' Koda, a 25-year-old pop idol famed for her cute and sexy look, said on her official website over the weekend.

Her agency, Avex Entertainment, said it was taking the matter seriously and announced a halt to promotional activities for her latest album, 'Kingdom,' which was released at the end of January.

Speaking on a popular radio programme, Koda said that her newlywed manager should have children soon for the sake of the mother's amnion, the part of the womb that protects an embryo.

'Mothers' amnion fluid is rotten once they turn around 35,' she said. 'I mean it. It gets dirty.' The soundbite was reproduced on Internet sites along with furious postings.

Some sites listed companies sponsoring her, urging consumers to complain.

There has already been an effect.

Kose Corporation, Japan's third-ranked cosmetics maker, halted online advertisements for its Visee brand, one of its major lineups, which features the pop star.

'We judged it necessary to suspend it as there are people who were offended,' a company spokesman said, adding they had not decided whether to scrap the campaign entirely.

Japan has one of the world's lowest birth rates, but a growing number of women, particularly professionals, are starting families later in life.

More than 17 per cent of 1.09 million babies born in Japan in 2006 were from women aged 35 or older, double the 8.6 per cent in 1990, according to health ministry data.

Koda has been romantically linked to Masahiro Nakai of the pop group SMAP and is not known to have any children.