The pair moved in opposite directions last summer, but the Englishman has turned down the offer with the hope of staying in France
Mbia joined the Rs from the Ligue 1 out last summer in a deal that saw Barton move in the opposition direction on loan.
Barton has since been vocal about his desire to remain at Marseille, but Mbia hinted at an impending exit from Loftus Road by publicly offering to again swap places with the Englishman.
"Do you want to rechange your seat with me?" Mbia tweeted to Barton on Monday.
Barton, diplomatically, replied, "How do I say this politically? Er...Nope!" before adding: "If you go down with a team, you should stay and help them up, mate. They need you all to stick together and help them back up."
Mbia removed the original tweet and insisted that his was not being serious, before admitting later: "No, it was not a joke, I removed my tweet under pressure. I want speak with [QPR] but they don't want.
"So... Seriously @Joey7Barton do you want rechange your seat with me?"
However, when contacted by The Guardian, the midfielder insisted the tweets were not a reflection of his own views, and were instead an anonymous hacker.
"I do not know how this happened, but someone must have got hold of my login and password because I did not write these things," he said.
"This was not me. I did not write the tweets, and I have made people at the club aware of that. I saw the messages this morning and spoke with the club about them, but now I see there are more appearing in my name."
Barton has recently been handed a suspended two-game ban by the National Council of Ethics in France for his comments about Paris Saint-Germain defender Thiago Silva on Twitter during April, meaning any further infringement on the social-networking website will see the punishment invoked.