A giant pharmaceutical company has apologised and withdrawn its magazine advertisements which claim swimmers can catch hepatitis A from the waters of the Bay of Islands.

The ads by GlaxoSmithKline for its hepatitis vaccine, Twinrix, horrified Northlanders when they appeared in North & South, Next and House and Garden.

They ask people to consider what they are getting themselves into when diving off a boat at the Bay of Islands, saying a bay full of boats is "potentially a bay full of pollution".

"All it takes is for one boat to discharge its holding tank of tampons, condoms, urine and faeces and you could be exposed to hepatitis A."

Yesterday, GlaxoSmithKline said it would stop using the ads.

Medical director Ian Griffiths said the company thought the Bay of Islands was a place people could catch hepatitis because many boats were moored there.

Hepatitis A is usually transmitted in food and water.

Northland officials said they were horrified by the ad.

Northland Regional Council chairman Mark Farnsworth said the council had conducted studies into water pollution in the area. Anyone who said it was polluted was wrong.