Rajapaksa has ordered the release of all Indian fishermenahead of his visit to New Delhi to attend Modi's swearing-in ceremony tomorrow, a presidential spokesman said.
This is the second instance when Sri Lanka is releasing Indian fishermen arrested by Sri Lankan Navy for poaching.
In March, Rajapaksa had ordered the release of arrested fishermen after India abstained from voting on an anti-Sri Lanka motion at the UN Human Rights Council in Geneva.
India was one of the 12 nations that abstained from voting on the UNHRC resolution, which prescribed an international probe into Sri Lanka's alleged rights abuses.
India had previously backed two similar resolutions against Sri Lanka moved by the United States.
Sri Lankan fisheries ministry officials, however, couldnot indicate the number of Indian fishermen currently in detention.
Sri Lanka's relation with India had soured during the government led by Congress.
Analysts here say Rajapaksa appears very keen to mend ties with his neighbour with the advent of Modi.