A missing Japanese woman and her Filipina mum were allegedly murdered over a financial row and found buried in their relative's backyard in the Philippines.

Air hostess Mai Motegi, 26, and her mother Lorry Litada, 54, both residents of Japan, flew to the Philippines to buy property worth around 5 million PHP (around 90,000 USD) in February.

They stayed with Lorry's older sister Ligaya Oliva Pajulas in Tayabas City, Quezon province, south of the capital Manila, but reportedly missed their flight back to Japan late last month.

Other relatives said they grew worried when the two failed to return their calls.

Police launched an investigation when another of Lorry's older sisters filed a missing persons report on March 29 stating that the pair had been unreachable since February 21.

Officers on March 14 went to Ligaya's house, where the two were last seen after arriving from Japan.

Investigators found that there was a patch of soft earth in the woman's backyard, prompting them to dig up the area. They discovered both Mai and Lorry buried in the shallow grave.

Police said Lorry had a puncture wound on her chest, while Mai suffered a broken jaw. They later found a suitcase containing their bloodied belongings floating in a nearby river.

Investigators said Ligaya, her husband, Charlie, and two other men were reportedly seen on CCTV dumping the luggage in the river before escaping on a tricycle.

Ligaya was taken into police custody. Police said she was rushed to a hospital in Quezon following an alleged suicide attempt by drinking insecticide.

Lieutenant General Rhoderick Armamento, chief of the Area Police Command – Southern Luzon, said Ligaya allegedly admitted to the crime on March 15.

He said: 'Investigations found that the suspects had been planning the crime since December, before the victims arrived in the country. They were having money troubles.

'We are looking at jealousy, anger, and finances as possible motives for the killings. The suspects will be charged with double murder.'

Meanwhile, Lieutenant Colonel Bonna Obmerga, Tayabas police chief, said the victims' five million PHP, intended to buy a house and lot in San Narciso town, was missing.

Investigations were ongoing.