The Japanese government is calling on its citizens to prepare for the worst-case scenario, should a major disaster hit the quake-prone archipelago: Stockpile toilet paper.

The industry ministry has launched a public awareness campaign ahead of the September 1 national Disaster Prevention Day, reminding citizens to have enough emergency supplies of food and sanitary products to survive the aftermath of a major earthquake.

"Be prepared and have no regrets," the ministry said in a statement, as it advertised a special exhibit on disaster preparedness to be held in its downtown Tokyo building.

"At times of major disasters, like huge earthquake, an insufficient number of useable toilets always becomes a problem," it said, adding that a toilet paper shortage compounds the issue.

In the wake of the 9.0-magnitude earthquake and killer tsunami disaster of March 2011, Japan experienced a shortage of many things including toilet paper, as families hoarded everything from water to gasoline, emptying store shelves even in areas relatively unharmed by the natural disaster.

The industry ministry has highlighted the vulnerability of Japan's toilet paper production capacity, which is 40 percent concentrated in Shizuoka prefecture, in a region where experts say a disastrous quake and tsunami could strike in the future.

The ministry is urging the public to keep enough rolls of toilet paper to last for at least one month, the period the government believes is needed for the toilet tissue market to return to normal after a major disaster.

"Using Disaster Prevention Day as an opportunity, please start stockpiling toilet paper at home," the ministry said, referring to the September 1 anniversary of the 1923 Great Kanto Earthquake, which killed more than 100,000 people.

The anniversary is used as a national training and awareness day to encourage people to plan ahead for disasters.

Toilet paper was the object of nationwide consumer hoarding during the oil shock of 1973.

The Japanese government and civil society routinely urge the public to keep a sufficient stockpile of emergency supplies, including a portable toilet, food, a flash light and cash.

But only a small fraction of the Japanese households admit to having readied an earthquake kit, despite the frequent reminders of the country's vulnerability to disasters.