Sri Lanka does not get enough investments for agro and metal industries, Amunugama said.
The authorities should open a separate zone for agro products, similar to that of BOI apparel zones situated next to Sri Lanka's international airport in Katunayake.
Red tape preventing the expansion of businesses must also be removed or Sri Lanka would lose its competitive edge to regional players, he said.
Most of the 50 investment deals signed on Tuesday were to set up or expand businesses in the telecom and IT sectors in Sri Lanka.
Airtel India was among the major foreign investors signing up to invest 150 million dollars to set up Sri Lanka's fifth mobile phone company.
Sri Lanka Telecom, the biggest fixed line operator also signed up to invest 200 million dollars over a two-year period to expand its network.