SINGAPORE - A lift in an Ang Mo Kio block of flats shot up 17 floors suddenly on Monday evening, trapping an Indonesian maid for about an hour and a half.

Ms Evi Lisnawati, 36, was on her way to pick up her employer's children from the tuition centre when the incident happened.

She entered the lift at Block 317 on Ang Mo Kio Street 31 from the fifth floor at about 7.15pm, she told The Straits Times.

At the ground floor, the lift door opened about 20cm, then closed back, she said.

She pressed the "door open" button but that did not work. It then went up to the third floor and stopped.

After pressing the button for a few more seconds, the lift began moving again. But instead of going down, it shot up.

"Very fast the lift got to the 20th floor," she said, describing how she fell down, and hit her back on the walls and the floor.

She heard a "bump", then the lift descended a little, and ended up stuck between the 19th and 20th floor.

"People on 19th floor can only see my legs," she said.

She called her employer to tell her what happened. Rescuers came soon, at around 7.30pm, but could not get the lift door to open, she said.

The Singapore Civil Defence Force (SCDF) said they were alerted to the incident at about 8.30pm.

SCDF said it freed Ms Evi with the help of a lift technician. By then, it was near 9pm, Ms Evi said.

She was assessed by paramedics but refused to go to hospital.

"I can just rest at home and take some medicine," she said.

It was a traumatic experience for Ms Evi, who said that she could not sleep until 1am on Monday night.

She still cannot sit down "properly", she said. Her employer asked her to rest, but she said she decided to start work and was going to cook dinner after the interview.

A spokesman from the Ang Mo Kio Town Council said that investigations are ongoing. The block of flats was built in 1994.