The Navy spokesman Kosala Warnakulasuriya said that they were observed some 300 nautical miles off the southern port of Galle.
They were rescued last night with the assistance of a merchant vessel, Navy said.
The rescued people, Tamils from the north, would be handed over to the police for further investigation, Navy said.
Over 600 people have been arrested in the last month for trying to illegally leave for Australia by fishing vessels.
