Dr McDonnell announced on Sunday his plans to stand down from his Assembly seat, but would not be drawn further as to when he expected to make the move.
Councillor Paula Bradshaw said: “It’s been clear from his poor voting record at both the Assembly and Westminster that Alasdair McDonnell has been incapable of fulfilling both his roles to even a satisfactory standard.
“While I welcome his commitment to finally give up his Assembly seat to provide better representative for the people of South Belfast in London, the move is long overdue and I must question why he has waited until now to do so. Why is May 2015 any different to May 2014?
“With Parliament due to meet for the first time with its new mandate next week, and with so many crucial issues on the agenda, it will be interesting to see how long he takes to find his Assembly replacement.
“As I engaged on the doors during the election campaign it was obvious there was wide-spread dissatisfaction with Dr McDonnell’s performance at Westminster during his last term of office. Perhaps this explains the reason why his vote in South Belfast was considerably down.”