Any public figure chatting to underage teens on social media needs to know they're toeing a fine line.

National's Chris Bishop is hitting back after parents made an anonymous complaint that he was inappropriately messaging teenage girls.

Parents had raised concern about the Hutt South MP communicating with young girls on the app - where messages delete after they've been read.

The Hutt South MP says there was nothing inappropriate about his messages, and he was simply trying to engage with young people. 

Bishop says he has since changed his settings so only people he personally knows can message him. 

 Rachel Klaver, Chief Strategist at consultancy firm Identify, says he may not have done anything wrong, but concedes it's not a good look and that people in public positions are best to steer clear of this type of engagement.

"I think it's just a raging inferno waiting to explode, to be honest. I think that it was probably a little bit naive of him, even if it wasn't him doing anything wrong.

"Teachers have the same difficulty, and teachers aren't allowed to actually talk to their students on Snapchat and things like that. I think it's one of those lines - you're a public figure, and you're responsible to people, you just need to know."

LISTEN ABOVE AS RACHAEL KLAVER SPEAKS WITH KATE HAWKESBY