Prime Minister Jacinda Ardern says New Zealand does not have the kind of Russian diplomat that is being expelled by the US and its European allies, but says NZ would also kick them out of the country if it did.

Dozens of Russian diplomats are being expelled from more than a dozen countries in a co-ordinated response to the poisoning of a former Russian spy in the UK.

Speaking to Morning Report today, Ms Ardern said the diplomats being expelled overseas were "undeclared intelligence officers", and she had been assured by MFAT that New Zealand did not have any operating here.

"But if we did, we would expel them."

She said she was not surprised that she had been advised that there were no such diplomats working in New Zealand, as it was unlikely the country would be top of the list for global intelligence services.

Watch Jacinda Ardern's full interview with Guyon Espiner on Morning Report: