UPDATE 1-Japan boosts rescue efforts as it warns of more rain in flood-hit areas

(Adds comments from PM Abe, Toyota, Mazda, and Panasonic)

TOKYO, July 7 (Reuters) - Japan on Tuesday warned of more heavy rain on the southwestern island of Kyushu and bolstered rescue operations as the death toll in flood-hit areas reached at least 50 and about a dozen people were reported missing.

The government said it would double rescue and relief personnel as heavy rain destroyed homes and caused landslides in what is shaping up to be Japan's worst natural disaster since Typhoon Hagibis killed 90 people in October.

"The rain front is expected to remain until the ninth (of July), and rain is expected over a wide front stretching from western to eastern Japan," Chief Cabinet Secretary Yoshihide Suga told a regular press briefing.

Police, Self-Defense Force and Coast Guard units are carrying out search and rescue efforts, said Suga, urging people to take the necessary precautions to keep safe.

Images aired by public broadcaster NHK showed swollen rivers, destroyed homes and roads covered in landslides.

Kyodo News reported 71 landslides across 12 prefectures, citing the land ministry, and said more than 1.3 million people had been ordered to evacuate.

Prime Minister Shinzo Abe said the government would double rescue and relief personnel, from day-earlier levels, to 80,000.

Some companies in the region have temporarily halted operations but Suga said he did not expect major disruptions to supply chains, as happened two years ago when deadly floods also hit Kyushu.

The government will continue to liaise with local firms, Suga said, adding: "We want to quickly take the necessary steps such as support for small and mid-sized firms depending on the situation ahead."

Carmakers Toyota Motor and Mazda Motor, and electronics conglomerate Panasonic Corp all halted operations at certain plants on Monday due to heavy rains.

Mazda resumed work at its Hiroshima and Hofu plants on Tuesday and Panasonic said its sensor plant in Kagoshima was operating normally on Tuesday.

Toyota said it would keep all three of its Kyushu plants closed on Tuesday after halting production the previous evening for safety reasons. (Reporting by Tim Kelly, Naomi Tajitsu, Makiko Yamazaki, Chang-Ran Kim, Chris Gallagher; Writing by Chris Gallagher; Editing by Ana Nicolaci da Costa)