The Health Ministry is searching for 55 New Zealand women, some of whom may have contracted hepatitis C at an Australian clinic.
The women were among 3500 patients seen at a Melbourne abortion centre, the Croydon Day Surgery, between January 2006 and December 2009.
A doctor who worked at the centre had hepatitis C and Victorian police are investigating whether he deliberately infected the women.
The Ministry of Health started tracing the 55 New Zealand women yesterday.
Ministry spokesperson Fran McGrath says it's a sensitive and potentially distressing situation, so they're being careful to protect the privacy and confidentiality of the women involved.
Testing results so far suggest that about 5% of all the women treated at the private clinic - which specialises in late-term abortions - may have contracted hepatitis C. On that basis, up to three New Zealand women may test positive.
Helpline offering advice, free testing
Victoria's chief medical officer, John Carnie, told Checkpoint that a cluster of hepatitis C cases was tracked back to the clinic but that he cannot explain how the outbreak occurred.
Mr Carnie says the infection control protocols and procedures at the clinic appear to be no different to those of other, similar clinics.
He says a helpline has been set up to offer advice and free testing. If women in New Zealand ring Healthline on 0800 611 116, they will be put through to the Hep C line in Victoria.
Hepatitis C is a potentially lethal blood-borne virus that causes inflammation of the liver.