South Korean police said they would seek an arrest warrant for a woman who set fire to her apartment building while trying to kill a cockroach with an improvised flamethrower, local media report.

One of the woman's neighbours died after falling to the ground in a failed attempt to escape through a window.

The woman, who is in her 20s, told police that she tried to torch a cockroach with a lighter and a flammable spray, adding she had used the method before. But on Monday, items in her home caught fire.

Police in the northern city of Osan said the woman could be charged with accidentally starting a fire and causing death by negligence.

Blasting cockroaches - with blowtorches or homemade flamethrowers - have emerged as a novel way of getting rid of house pests, made popular by videos on social media.

In 2018, an Australian man set fire to his kitchen while trying to kill cockroaches with a homemade flamethrower made from insect spray.

The woman who died in the Osan city fire, a Chinese national in her 30s, lived on the fifth floor of the building with her husband and two-month-old baby.

When they realized that a fire had broken out, the couple opened their home window and called for help.

They handed their baby through the window to a neighbour in the adjacent block, before trying to evacuate themselves.

The woman's husband managed to climb over to the next block. She tried to do the same, but fell from the window. She was taken to the hospital and pronounced dead hours later.

Police said they believed the couple had tried escaping through the window because thick smoke from the fire had blocked the stairway, local media report.

The building houses commercial shops on its first floor and 32 residential units from its second to fifth floor.

Eight other residents suffered from smoke inhalation because of the fire. (BBC)