TOKYO: Japan's Hiroshima prefecture said on Friday it will carry out large-scale polymerase chain reaction (PCR) testing to curb the spread of coronavirus, a rarity in a nation that lags far behind many other countries in the number of tests conducted.

The western Japan prefecture aims to conduct PCR tests for 800,000 people in the city of Hiroshima, which has a population of 1.2 million.

The 800,000 comprises residents in the city's four wards hardest hit by the virus and workers who commute into the area.

Hiroshima prefecture is not covered by the state of emergency currently in place for Tokyo and 10 other prefectures, but Hiroshima city has been struggling to contain a steep climb in COVID-19 cases in recent weeks.

"I believe tests of this size have rarely been seen (in Japan)," a Hiroshima prefecture official told Reuters.

"They say coronavirus is transmissible two days before one develops symptoms, and some of those who are infected do not necessarily visit clinics in a timely manner. We want to catch those people and prevent further infection," he said.

The prefecture aims to launch the tests by the end of the month.

Japan conducted an average 0.43 tests per 1,000 people a day in the week to Jan. 12, according to Oxford-linked tracker Our World In Data. That compares with 8.41 tests in Britain and 3.93 tests in the United States.

Japan has seen coronavirus cases total around 310,000, with 4,340 fatalities, according to public broadcaster NHK.