The book, "Promoting economic cooperation in South Asia: beyond SAFTA" argues that the South Asian Free Trade Agreement has potential to accelerate economic growth in the region.
It contains the views of academics, policy makers and private sector leaders.
Kelegama said India is now the largest import source for Sri Lanka as well as the third largest destination for the island's exports.
Sri Lanka is strengthening its trade links with other south Asian countries already having bilateral free trade deals with India and Pakistan.
"This is particularly important at a time when preferential access to the EU market via GSP Plus is in doubt," said Kelegama.
He was referring to the European Union decision to withdraw the GSP Plus trade deal giving duty free access for exports because of alleged human rights concerns.
"The book argues that this market still remains unexploited."
Trade among south Asian countries is still around five percent compared to 25 percent in South East Asia, 54 percent in the EU and 59 percent in North America.
"The existing pattern of intra-regional trade in south Asia fails to capture the extent of complementarities in the region due to high incidence of non-tariff barriers and informal trade," Kelegama said.
"This book argues that three-fourths of the intra-regional trade potential remains to be exploited which SAFTA can hope to realize."
Although south Asia is one of the world's fastest growing regions, it is home to over 40 percent of the world's poor and fares poorly on indicators such as education, health, nutrition and sanitation
"This is worrying and the danger is that the current downside risks posed by the slow recovery of the external environment could slow down south Asian growth further and further aggravate poverty and human development," Kelegama said.
The study argues that south Asia can face the challenge more effectively with deeper regional economic integration as it is one of the world's least integrated regions.
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