Wharton said there was an increased "appetite on US Congress to take a fresh look on ZIDERA," adding that the legislation was not something President Barack Obama could unilaterally change, but it called for parliamentary action.
"I don't think it would take them (US Congress) much longer," said Wharton on Tuesday. He said it could take about six months before ZIDERA could be lifted or modified.
"One of the things I hope to do is to bring some influential members of the Congress to visit Zimbabwe sometime in the next six months or so partly with the idea of looking at how ZIDERA could either be removed or modified," he added.
He however, ruled out immediate changes to zidera until after next year's elections.
"I think that if this country moves forward on the constitutional reform, referendum and on elections there could be good chance ZIDERA could be removed very quickly," explained the envoy.
ZIDERA, which among other things prohibits US financial institutions from extending lines of credit to Zimbabwe, was passed in 2001 to provide for a transition to democracy and to promote economic recovery in the country.
The US imposed targeted sanctions on President Robert Mugabe and his inner circle, including companies linked to ZANU-PF citing electoral fraud and human rights abuses.
But President Mugabe argues that the restrictive measures were imposed on him and his inner circle due to opposition by the US and its allies against his land reforms.
Wharton failed to meet with Bulawayo governor Cain Mathema, who on Tuesday said had no time to entertain the diplomat whose country imposed sanctions on Zimbabwe.
Wharton regretted that Mathema was unable and unwilling to meet with him, adding that he believed if he had had audience with him they were going to find common ground.
The US diplomat said relations between the US and the Zimbabwean government remained frosty.
"The relationship between our two governments is not very good and it is my ambition to find ways to build up on the work of my predecessor, Ambassador Charles Ray.
"It is my role to move that official relationship beyond its current not very good status. It is not going to be easy," he said.