Modelling by New Zealand researchers shows how the country is buying time in the fight against Covid-19.

There is no certainty the four-week lockdown will be enough. Researchers say that left unchecked the virus would infect 89 percent of the population and up to 8,000 people would die.

The good news is with the current strict measures fatalities would drop considerably. But that scenario requires the restrictions to be in place for some time - so how long?

University of Auckland's Sean Hendy is one of the modellers. He talks to Lisa Owen.