He said work on 31.6 kilometer stretch financed by the Japan Bank for International Co-operation (JBIC) and a 29.
3 kilometer segment finance by the Asian Development Bank are being wrapped up.
But about 20 percent of the work in the last stretch of the 95 kilometer expressway to Galle remains to be completed, he said.
Pemasiri said construction of a fuel station in Kaluthara, mid-way on the toll road has also begun.
The toll road terminates in Matara, 135 kilometres from the starting point in Sri Lanka's capital Colombo. The Galle to Matara segment was delayed due to the need for additional finances.
Sri Lanka later got China's Exim Bank to finance the final section. The construction contract has been given to China National Import and Export Corporation.