The Commonwealth suspended Pakistan's membership following the military coup that saw Parvez Musharraf seize power in 1999, but it was lifted in 2004 on expectations that Islamabad would undertake democratic reforms.
"Musharraf should decide if he wants to be the 'operational' head of the army or the democratic President," McKinnon said a day before the opening of a Commonwealth Finance ministers' meeting in Colombo.
"I say this because it is not within the Commonwealth values that a person should hold leadership of both the operational command of the army and the presidency of the country," he said.
"This is made well known to Pakistan. These issues I hope would be resolved by the time our leaders meet in Uganda in end of 2007," he added. "Of course that time does coincide with Pakistan election, which too have to be held by Jan 2008 or in the latter part of 2007," McKinnon said.