Eight Indian engineers and more than 100 Afghan workers were killed in Taliban attacks since the construction of the road began more than two years ago, said Minister Wali Mohammad Rasouli.
There were a few sections of route that had to be touched up before a handing over ceremony was held in a few weeks, he said.
Landlocked Afghanistan relies mostly on Pakistan's port of Karachi for goods arriving by sea, including supplies for the nearly 70,000 international soldiers helping to fight a Taliban-led insurgency.
The road was initially budgeted at 80 million dollars but is reported to have cost 185 million dollars, in part because of the high security risks of operating in southern Afghanistan.
The route, already open to traffic, is a welcome alternative, since goods can sometimes be held up on alternate routes from Pakistan, where they are also often subjected to high taxes, Rasouli said.
"The new road is very important for us," he said. "Now we have an alternative road to use when Pakistan creates problems and obstacles for our traders on their ports."
Islamabad also does not allow goods from India -- its enemy -- to transit through Pakistan into Afghanistan.
Kabul has a good relationship with New Delhi, one of the main financers of its efforts to rebuild from decades of war although it has not sent troops to join the international military effort against the resurgent Taliban.
However its ties with Islamabad are strained, notably over the unrest.
Kabul alleges that elements in Pakistan, including its government, are supporting the Taliban. Islamabad was one of only three countries that recognised the 1996-2001 Taliban regime.