"There is no justification to keep them," Ghanim said, adding that Libya had undertaken many steps to improve its relations with the United States after years of international isolation.
Libya was under international sanctions since 1992 over the bombing of PanAm flight 103, a US airliner, over the Scottish town of Lockerbie that killed 270 people in December 1988.
The United Nations lifted its embargo in September after Tripoli agreed to pay $2.7 billion in compensation and accept responsibility for the bombing, but US sanctions have remained in place.
In an interview with the New York Times on Friday, Ghanim urged Washington to lift its sanctions by May 12, the deadline for Tripoli to complete the compensation payments to victims' families.
He said the United States should act quickly to reward Libya for its decision last month to dismantle weapons of mass destruction programmes and allow international checks of its nuclear facilities.
Libya so far has paid four million dollars to each family of the Lockerbie victims. Under the terms of the agreement, it may forgo paying the outstanding compensation payments if US sanctions are not lifted by May 12.
"What Libya pays in the future depends on the gestures which the Americans are called to make and on which we agreed," Ghanim told AFP. "We will act in accordance with the agreement."
US not in hurry
The United States said on Friday it would not be hurried. "As far as the subject of lifting sanctions goes, our focus is on Libyan actions and Libyan performance," said a State Department spokesman.
The two countries broke off diplomatic ties in 1981, and US economic and political sanctions have been in place for more than two decades.
"As far as the subject of lifting sanctions goes, our focus is on Libyan actions and Libyan performance"
US State Department
Libya's decision to abandon weapons of mass destruction was taken "not to satisfy any party. We took it because we want to develop our country's economy and improve the social standards of our people," said Ghanim.
The prime minister, who is a trained economist and headed the government since June, said the lifting of US sanctions would "serve oil companies" in the United States that have been banned from importing Libyan crude since 1982.