Mr McCarten was confirmed in the role at a joint press conference with Mr Cunliffe yesterday. He said he had taken the job despite initially being critical of Mr Cunliffe because he was "pleasantly surprised" by the direction the leader was taking the party.
"We have got to know each other very well. The chemistry has been extraordinary. We have a lot of similar beliefs, and I thought this man could be the Prime Minister and should be the Prime Minister."
Asked if he and Mr Anderton had reconciled since the then Deputy Prime Minister split from the Alliance in 2002, Mr McCarten said the differences at that time were "profound" but "we will work together on this campaign".
Mr Cunliffe would not say if Mr Anderton had agreed with the choice of Mr McCarten, "but Jim is showing by his actions that he's coming home to Labour".
However, Mr Anderton made it clear he was not coming home, saying he helped Labour in the 2013 Christchurch East byelection and in his old electorate of Wigram in 2008 "but I will not be helping in the general election campaign. I don't want there to be any confusion."
He had not spoken about Mr McCarten publicly since the Alliance split "and I don't intend to start now".
Mr McCarten split from Labour in 1989 in protest at Rogernomics and joined Mr Anderton to set up NewLabour, which merged with others to become the Alliance. Mr Anderton set up the Progressives in 2002 after disagreements over the governing relationship with Labour. Since then, Mr McCarten has helped set up the Maori Party, the Mana Party and the Unite trade union.
He has been critical of Mr Cunliffe in his columns for the Herald on Sunday, including suggesting he resign from politics for failing to pull his weight in 2012 and accusing him of narcissism and "the same phoniness as the Republican US presidential nominee Mitt Romney".
Mr Cunliffe said he did not want a "yes-person". He also rejected claims by Prime Minister John Key that the McCarten appointment signified a swing to the far left.
