Labour MP Trevor Mallard and Green MP Metiria Turei are no longer Facebook friends.
Mr Mallard thought the Green Party co-leader had been rude on his page so he defriended her and she blogged that she was sad about that.
Mr Mallard hit a snag in using the social networking site to promote political messages when Ms Turei questioned his post about the minimum wage, asking why Labour didn't increase it more while in government.
"We moved it from $7 to $12. Trajectory would have had it at $14. Not much real help from you guys esp since Russel (Norman) started cuddling tories," he responded.
Ms Turei told him off for getting personal but continued to argue Labour could have done better.
Mr Mallard said he struggled to understand why she was attacking Labour rather than National.
"And that's how our FB friendship came to an end," Ms Turei wrote yesterday on Frogblog, the Green Party blogsite.
"The beauty of Facebook is that politicians like Trevor and I can discuss issues in the public eye. It means we are challenged by others to answer for our views, decisions and behaviour - which is great. It's one reason why I like to use Facebook to ask questions: Have I got this right? ... So where is the commitment to an open dialogue if you get defriended - for disagreeing?"
She said he was being silly and she would ask to be friends again.
Mr Mallard commented on Labour's Red Alert site that Ms Turei should keep attacks on Labour to her own website.
He admitted being new to social media sites and said he saw his Facebook page like his home.
"I choose who is there. While there are lots of discussions initiated by constituents I decide whether they run or not. But the idea of politicians using the comments section of my status to attack me just doesn't seem right."
However he agreed to be friends again.
"But I will watch her manners carefully."
Mr Mallard has more than 3000 Facebook friends.
NZPA