The Ministry of Health has begun receiving supplies of a second anti-viral to augment supplies of Tamiflu in its measures to contain swine flu.
New Zealand has five confirmed and 14 probable cases of swine flu, also known as H1N1. In total, 464 people are in isolation throughout the country.
Ministry officials had ordered 135,000 courses of Relenza to add to the stockpile of 1.2 million treatment courses of Tamiflu.
They say they have received 10,000 courses, 1,000 of which have already been distributed to district health boards. The remainder has been added to the stockpile, with the final 125,000 courses due in the country by 12 June.
The Health Ministry is advising people not to buy Tamiflu over the internet, saying there is no guarantee of the safety, efficacy or authenticity of Tamiflu bought over the internet.
It says anyone who needs Tamiflu for swine or seasonal flu, because they have been to North America or Mexico or been in close contact with someone who has, will get it for free.
Those with seasonal flu can have Tamiflu prescribed after seeing their doctor or pharmacist, but they will have to pay for the prescription.
Meanwhile, the ministry is considering whether the usual surveillance of seasonal flu should be stepped up.
Virologist Lance Jennings says the H1N1 influenza virus appears to be a mild infection that is not very transmissible.
He says it may burn itself out. But it could also become more virulent as New Zealand enters the southern hemisphere winter and begin spreading like a common flu, possibly with increased severity.
The ministry says that possibility is being closely monitored internationally and it may increase surveillance of regular flu.