Police in Indian Kashmir have warned residents to build underground bunkers to prepare for a possible nuclear war in the disputed region, which is on edge after a string of deadly border clashes.

The warning comes despite a ceasefire which took hold last week in the scenic Himalayan region, after the Indian and Pakistani armies agreed to halt cross-border firing that had threatened to unravel a fragile peace process.

"If the blast wave does not arrive within five seconds of the flash you were far enough from the ground zero," says the notice, headed "Protection against Nuclear, Biological and Chemical (NBC) Weapons".

It warns of "initial disorientation" from a nuclear attack, saying the blast may "carry away many prominent and familiar features".

The instructions were issued Monday in a local English-language Greater Kashmir newspaper by the State Disaster Response Force, which is part of the police.

They vividly describe a nuclear war scenario to prepare residents to deal with "the initial shock wave".

The notice tells them to "wait for the winds to die down and debris to stop falling".

"Blast wind will generally end in one or two minutes after burst and burns, cuts and bruises are no different than conventional injuries. (The) dazzle is temporary and vision should return in few seconds," it says.

It tells residents to build toilet-equipped basement shelters "where the whole family can stay for a fortnight", and says that they should be stocked with non-perishable food.

Nuclear-armed India and Pakistan have fought three wars since partition in 1947, two of them over the Kashmir region that both nations claim.

Police confirmed they issued the notice but said it "should not be connected with anything else", in an apparent reference to border tension.

The notice is part of regular year-round civil defence preparedness, Mubarak Ganai, deputy inspector general of civil defence in Kashmir police, told AFP.

An Indian counter-terrorism expert criticised the warning as valueless for Kashmiris, who could be forgiven for imagining war was an imminent prospect.

"There can be no conceivable motive for issuing a notice like this," Ajay Sahni, executive director of the Institute for Conflict Management in New Delhi, told AFP.

"Such information collected from here and there is not worth the paper it is printed on," he said, adding that "there can be no preparedness for such an eventuality".

There has been calm along the de facto border in Kashmir since commanders of the two sides agreed last Thursday to halt the cross-border firing.

Pakistan says three of its soldiers died in the firing while India says it lost two of its soldiers -- marking the worst violence along the frontier dividing the region since the two nations nearly went to war in 2003.