Many patients, however, didn't want to chance the side effects of interferon and others couldn't be put on it because of the psychiatric risks.
The cure rates of the new combination oral therapies were 95 per cent or higher and they had few side effects.
"Because these treatments are so short duration and so well tolerated, I think that, provided they're affordable, they will be able to be given in general practice [rather than hospital clinics]."
Pharmac approved state-funding of boceprevir last year for some patients. One of the new drugs described by Professor Gane, sofosbuvir, has been approved for use in New Zealand and an application for state funding will go before a Pharmac committee in August.
Professor Gane said the predicted doubling of liver cancer cases by 2020 - there were 210 cases referred to his hospital last year, compared with 52 in 2004 - could be avoided, "if we get these treatments available and get people tested".
But that highlights a public blind-spot for being at risk of hepatitis C. The leading risk factor in New Zealand is having been an injecting drug user.
Professor Gane urges everyone who did this, even in their distant past, to have a hepatitis C blood test, which can be arranged by a GP or by hepatitis awareness organisations in some parts of the country.
Case study
Glenn Macrae thinks he probably had hepatitis C for a decade before the first signs of it were picked up by a blood test.
Even then the diagnosis was vague: "hepatitis-type virus neither A nor B". Scientists didn't discover the C virus until 1989 and Mr Macrae's first doctor visits for it were in about 1981, when he felt like he had the flu for a couple of days.
The Titirangi gardener and married father of two adult children is now aged 63 and he has had countless medical consultations about the virus. He has also been cured, by the third of three gruelling courses of medicines.
Quietly spoken and calm, Mr Macrae declares himself "ecstatic" to be free of a disease that robbed him of energy, often left him feeling unwell and could have killed him.
"Nobody could understand why is Dad sitting inside, why doesn't he come outside and join us, why is he grumpy all the time."
He doesn't know how he caught the virus, but says it wasn't injecting illicit drugs because he never did that. He wonders if it came from contaminated materials used in the the first tattoos done on his arms when he was a young man, or from blood products used to treat him in hospital after a serious car crash when he was 18 or 19.
He wasn't properly diagnosed until 1999 when he was feeling "crook" again and saw a doctor. He was referred to the Auckland Hospital liver clinic under specialist Professor Ed Gane, who put him on interferon and ribavirin.
But the therapy was stopped after three months. The drugs were not reducing the number of hepatitis C viruses in his blood and he was suffering horrible side effects: flu-like symptoms, rashes and itches, sweating, nausea, hair-loss - and depression, "which I'm still fighting today".
In 2008 he went on "pegylated" interferon with ribavirin. He took this for a year and the side effects came back. His virus count dropped below the detection level, but bounced back after the end of treatment.
In 2012 he was offered the same drugs plus boceprevir.
"I had just had an ultrasound and they said my mild fibrosis [liver scarring] had turned to severe fibrosis. It wasn't a good outlook. The next stage is cirrhosis then cancer and ultimately death."
"It's like a sword waiting over your neck."
He suffered a heart attack three months into his treatment and had a stent placed in a heart artery, although this set-back wasn't thought to be related to the hepatitis therapy.
After a year of treatment he was clear of the virus and blood tests over the following year confirmed he was cured. Scans of his liver have shown it is repairing the scarring caused by the virus.
Mr Macrae said his health now was "excellent", apart from back problems caused by a fall, and he had cycled the Otago rail trail with his wife and daughters.
Hepatitis C
• A virus transmitted by blood
• It is estimated that 50,000 New Zealanders have the virus
• Only half of them have been diagnosed
• Illicit injecting drug use is the main way New Zealanders have been infected
• Less common ways include through contaminated blood products in healthcare, medical care in a developing country and tattooing
• Can damage the liver and cause cancer
• Today is World Hepatitis Day
• More information: www.hepatitisfoundation.org.nz.