New Zealand police have been asked to investigate whether the qualifications of former immigration department executive Mary-Anne Thompson had been falsified.

The allegations concern a PhD from the London School of Economics which Ms Thompson has claimed to have obtained.

An LSE spokeswoman told the New Zealand Herald that a search has found no evidence that Ms Thompson received a PhD from the London School of Economics.

Ms Thompson was forced to resign on Tuesday following allegations that she helped family members from Kiribati with their residency applications.

The State Services Commission launched an inquiry into the claims, and into the handling of the matter by the Department of Labour, which oversees the immigration service.

Produced by Radio Australia and Australia Network