Senior shadow cabinet minister Yvette Cooper has rejected suggestions that Ed Miliband had made a lack-lustre start to his time as Labour leader.
Ms Cooper and her husband Ed Balls have both been tipped as possible successors to Mr Miliband if he is ousted from the leadership.
But she insisted that the shadow cabinet team were "very supportive" of their leader and said he had already laid some punches on Conservatives over issues like housing benefit and school sports.
Speculation over Mr Miliband's future has heightened following poor performances in a BBC interview and at Prime Minister's Questions, while his shadow chancellor Alan Johnson has openly disagreed with him on key issues like the future of the 50p top rate of income tax and university fees.
Ladbrokes has halved its odds on Mr Johnson replacing Mr Miliband from 33-1 to 16-1 after receiving a "substantial gamble" on him, and cut the odds on a change in Labour's leadership before the next election from 5-2 to 2-1.
Mr Miliband has also faced criticism for taking two weeks' paternity leave shortly after he became leader.
But Ms Cooper told BBC1's Andrew Marr Show that he was "exactly right" to take time off after the birth of his son Samuel.
She added: "He is doing a very good job and has got a very supportive team around him.
"If you look at some of the things Ed has been focused on - housing benefit reforms are now being delayed, on school sports there's been a rethink. He is right to focus on these issues."
Ms Cooper said she backed Mr Miliband's preferred option of a graduate tax to fund universities.
