Former National MP Andrew Falloon won't be charged over unsolicited images

Former National MP Andrew Falloon will not be charged after he was accused of sending inappropriate images to several young women.

Falloon resigned as MP for Rangitata in July after pressure from newly minted National leader Judith Collins, after she was alerted to the images by Prime Minister Jacinda Ardern.

Police launched the investigation into allegations raised by Collins and the initial complainant,  the results of which were released on Friday.

"Whilst we acknowledge that the material sent was distressing for those who received the images, the investigation found that the actions did not meet the criminal threshold necessary to support a prosecution, and no criminal charges will be laid," a police spokesperson said.

"We have today advised the complainants of the outcome of our inquiry."

In a statement at the time, Falloon said he had been dealing with "unresolved grief" following the recent suicide of a friend.

He said: "I have made a number of mistakes and I apologise to those who have been affected".