Before the team left for the West Indies, Misbah was told that he needed to do more as captain of the Test and one-day sides.
"I told him (Misbah) clearly that his performance as captain was not good enough and he needed to improve his performance or else we would have to review things," Sethi said.
The PCB chief said he had also conveyed to Whatmore the same thing.
While Whatmore took over as head coach in March, 2011 replacing Mohsin Khan, Misbah has remained the Pakistan captain since late 2010.
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Pakistan's recent performances in South Africa and the Champions Trophy have raised questions over the future of the Misbah-Whatmore combination.
Sethi also insisted that he had accepted the challenge of looking after cricket affairs for the sole purpose of bringing democracy into the board and expanding the talent base for Pakistan cricket.
Sethi said he would soon be appointing a new selection committee.