"It is very likely that the talks will bear results, if the other party comes to the negotiations with serious will," Xinhua quoted Zarif as saying in a press conference.
However, if the sides cannot reach an agreement, Iran could return to its former nuclear policies, the minister added.
It is too early to say whether the nuclear talks have been successful or failed, he said, adding that there are still steps to be taken before July 20.
"Our words have been logical from the beginning and we do not demand beyond our legal (nuclear) rights. To this end, we are ready to remove legitimate concerns (of the world)," he said.
The fifth round of Iranian nuclear talks concluded on Friday in Vienna with some progress on drafting the framework of a final deal, while gaps over some topics remained.
In the latest talks, Iran was asked to decrease the number of centrifuges to ensure that it cannot quickly produce enough material for a nuclear bomb. But Iran said it needs more centrifuges to produce uranium to fuel more nuclear plants for electricity.
Iran also demanded total removal of international sanctions, including the oil embargo, which is biting its economic lifeline.
Under the interim Geneva deal last November, Iran undertook to freeze some controversial nuclear activities in six months in exchange for a limited easing of western sanctions.
The world powers and Iran will meet again July 2 in Vienna for the next round of talks.