The fishermen were arrested on Monday night at Talaimannar and Kangesanthurai off the northern coast of Sri Lanka, the Sri Lankan navy said.
They have been handed over to the fisheries inspection offices in Jaffna and Mannar, the Sri Lankan Navy said.
The arrests followed Sri Lankan government claims that new legislation is being planned in order to confiscate equipment of Indian fishermen allegedly poaching in Sri Lankan waters.
A fisheries department official in Tamil Nadu said the 34 fishermen were arrested today in separate batches by Sri Lankan naval personnel near Katchatheevu in the Palk Straits and close to the Lankan coast respectively.
The department's assistant director told PTI that 23 fishermen from Kottaipattinam in Pudukottai district were arrested at Neduntheevu close to the Sri Lankan coast while others were arrested while fishing near Katchatheevu.
The Sri Lankan navy allegedly damaged two boats by forcing them to collide, seized seven boats and also ruined 40 fishing nets, he said.