The two were injured in the blast in Jaffna's Pallai area, the information department said.
Police said both victims work as fishermen and were attempting to use bombs, hidden from LTTE days, for fishing.
The explosion took place while they were digging out a bomb, they said.
In another security breach, two policemen were injured when they were attacked by a group of people in Jaffna's Chunnakam area.
Five policemen were remanded for the killing.
The police said the two incidents were not linked and today's attack on the policemen was carried out by an extortionist gang.
Disclaimer: No Business Standard Journalist was involved in creation of this content