NSW MPs formally approve Carr replacement

It's finally official - Bob Carr is no longer a senator.

Mr Carr had technically already been replaced by Labor's Deb O'Neill shortly after announcing his retirement last October, but a constitutional quirk meant he became a senator again this week.

Legal advice given to the state government said that Mr Carr could only be replaced once the Senate entered its new term, on July 1.

That forced NSW MPs to return from their winter break to convene a "slimmed-down" joint sitting, so that the former NSW premier and foreign minister could be excused from the Senate and return to private life.

Ms O'Neill, who was present in the chamber, was formally endorsed by state Opposition Leader John Robertson to replace Mr Carr.

The president of the house asked if there were any other suggestions to replace Mr Carr, to which coalition MPs sledged: "Bring back the Faz", referring to upper house Labor MP Amanda Fazio, who was recently dumped from the party's ticket for the 2015 state election.

Ms Fazio later launched a stinging attack against her party's right faction, saying its nomination processes were "corrupt and undemocratic".