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.