Sri Lankan industry cannot match that of India's, he warned.
"The existing free trade deal had not brought the expected benefits and the expected reciprocity did not come," he told a news conference Wednesday.
He warned that there were fears the new agreement could open up the doors to Indian investors and professionals while Sri Lankan firms and professionals would remain shut out of the Indian market.
Wickramasingha said his firm, Ceylon Biscuits, exports biscuits, confectionary and fast moving consumer goods to India but had encountered numerous difficulties, as had other exporters.
Sri Lankan exporters were being blocked by bureaucracy, red tape and the unhelpful attitude of Indian officials.
"We should look at it in a more practical manner," Wickrama