The forest industry's heavy dependence on a single tree species leaves it more vulnerable to attack by invading pests and diseases, a visiting specialist says.
Sandy Liebhold, an insect scientist with the United States forest service, is in New Zealand for an international conference on forest biosecurity in Rotorua.
Mr Liebhold says New Zealand is regarded as the world leader in managing insect invasions, after its success in eradicating the painted apple moth through an intensive spraying programme in the Auckland region five years ago.
He says despite this, the country's almost total reliance on radiata pine, which makes up nearly 90% of its commercial forests, is a biosecurity risk.
However, MAF Biosecurity's post-border director, Peter Thompson, says the eggs might all be in one basket, but he says it is a "strong, pretty well-protected basket".