A Landcare Research scientist has highlighted a pollination paradox for New Zealand when it comes to the honey bee.
Dr Linda Newstrom-Lloyd says honey bees, and to a lesser degree bumble bees, are essential to food production.
They are the main pollinators of the fruit and vegetable crops which provide about a third of the food eaten in New Zealand. They also pollinate the clover in pasture grazed by livestock.
Honey bees also contribute to native plant pollination.
But Dr Newstrom-Lloyd says bees also play a conflicting role in their pollination work by helping to spread some of New Zealand's worst weeds.
She says the elimination of weeds like gorse and broom could also put native insects under pressure as honey bees look for alternative food sources.
She says this highlights a balancing act required to manage bee populations and the need to provide other pollen sources.