They were arrested 10 nautical miles north off the eastern coast of Trincomalee, Naval spokesman Commander Kosala Warnakulasuriya said.
Four women and two children are among the group of 83 people, who are all residents of the north and east provinces, the spokesman said.
The detection was the first since Australia's parliament on Thursday voted to set up off shore processing centres for asylum applications.
Australian government would now send boat people to Papua New Guinea and Nauru to have their asylum applications processed.
Sri Lankan police said that over 900 people have been arrested so far this year for trying to illegally leave for Australia.