No-fishing zones will be created along 7,500 kilometres (4,650 miles) of designated coastal zones to protect "important" government facilities such as nuclear plants, ports and dams, the senior home ministry official said.
"In the first step, no fishing will be permitted within 500 metres (1,650 feet) of four nuclear installations in Tamil Nadu state and one in Mumbai," he added.
Weaknesses were exposed in India's coastal security last November when 10 Islamist gunmen came by sea from Pakistan and attacked Mumbai, killing 166 people.
The official, who asked not to be named, said the decision was made on Wednesday during a high level security meeting involving the home ministry, the coast guard and the Indian navy.
The western state of Gujarat had also been advised to set up similar no-fishing zones around two dams and several other vital installations in the coastal region, he added.
A similar advisory will also be sent to prevent possible infiltration by remnants of Sri