"We will allow buses to travel on the road after four or five months," minister Kothelawala told reporters.
"But buses with belts in all seats, and door that can be closed will have to be imported."
Initially only five bus services will be permitted, Kothelawala said. There have been concern that public transport was not feely allowed on the road.
The four lane expressway will be ceremonially opened by President Mahinda Rajapaksa on November 27.
On November 19 and 20 pedestrians and bicycles will be given a one-time opportunity to go on the road, officials said.
But after the expressway opens, bicycles, three wheeled vehicles, tractors will not be allowed.
The road has a design speed of 100 kilometres with a minimum speed of 80 kilometres.
The 96 kilometer expressway runs from Colombo to Galle in the South of the island, and is part of a longer 136 kilometer road to Matara at the southern tip of the island.
The road will have paramedics and a breakdown service