South Korean police announced on Thursday that they had arrested a 42-year-old woman suspected of murdering two children in New Zealand in 2018 and concealing their remains in suitcases.

The bodies of the two children were found last month after a New Zealand family bought abandoned goods, including two suitcases, from a storage unit in Auckland in an online auction. The family is not suspected of involvement in the children's death, police have said.

The children were between 5 and 10 years old at the time of their death, which is believed to have occurred in the Auckland area. Police said the suitcases had been in storage for at least three to four years.

What have police said about the arrest?

Police from both countries said that the woman, who is believed to be the mother of the two dead children, was arrested following a request from New Zealand.

South Korean police said they detained the woman in the southeastern port city of Ulsan.

"Police arrested the suspect at an apartment in Ulsan on Thursday following a stakeout with tips on her whereabouts and CCTV footage," Seoul's National Police Agency said in a statement.

The police said the woman was born in South Korea and later moved to New Zealand, where she gained citizenship. She returned to South Korea in 2018, according to immigration records.

The Seoul High Court will now decide in a review of the case whether she should be extradited, said Park Seung-hoon, an official at the National Police Agency.

Park said a date hadn't yet been set but that the review must take place within two months.

New Zealand and South Korea have a treaty allowing for the extradition of suspects to each country.

A New Zealand police official, Detective Inspector Tofilau Fa'amanuia Vaaelua, said in a statement that the investigation had been "very challenging."

"To have someone in custody overseas within such a short period of time has all been down to the assistance of the Korean authorities and the coordination by our New Zealand Police Interpol staff," he said.