Despite 300,000 people remaining homeless 19 months after the disaster, nearly a quarter of the 14.9 trillion yen (£93bn) has paid for unconnected work, sparking outrage over the slow pace of reconstruction work.

Cash has been siphoned to pay for roads in Okinawa, an advertising campaign for Japan’s tallest building, subsidies for a contact lens factory, strengthening visa screening for foreigners, and eight billion yen was used to buy components for high-tech products.

Ironically, 4.2 billion yet was spent on disaster-prevention equipment, which was sent to South East Asian countries, a government audit shows.

Nearly 19,000 people were killed in the March 2011 earthquake-triggered tsunami, and 340,000 people are still living in temporary camps.

The government admitted diverting the funds had been a mistake, adding unrelated projects will be “strictly wrung out” of the budget.

Prime Minister Yoshihiko Noda said in a speech to parliament: “It is true that the government has not done enough and has not done it adequately.

“We must listen to those who say the reconstruction should be the first priority.” The news has sparked outrage, with officials hitting out at the government’s slow progress in rebuilding Japan’s devastated northeast.

Chizuo Hayashi, from the Fukushima reconstruction bureau, told AFP: “We need lots of money for decontamination of radiation, but the implementation of budgeted projects tends to be delayed.

“We residents in the disaster-hit area hope the reconstruction budget will be used primarily for rebuilding our communities.

”The figures came in a government-commissioned 141-page audit released last week detailing 192 The audit report said only half of the money set aside for reconstruction had actually been spent, blaming a shortage of staff in local municipalities.

In December last year the government admitted around 2.3 billion yen from the fund was being used to boost security around its controversial whale hunt.