Rescue teams raced to save a one-year-old girl that had fallen into a 50ft-deep well while playing in Thailand.

The youngster named Tasa Mo-ei plunged into the narrow pit when she wandered away from her parents who were working in nearby fields in Tak, northern Thailand, on February 6.

Police, firefighters, and disaster response officers were called to a cassava field in the border province next to Myanmar after at around 4pm local time.

Footage from the early hours of February 7 shows the rescuers lowering a tube of flowing oxygen into the hole before digging up the ground using excavators and pickaxes.

The child's parents Atay, 20, and Necho, 26, said they were hired to work in the fields and had brought their daughter along. They left the toddler unattended under the shade of a tree and went to plow at the plantation, only to find her missing when they returned.

Frantic Atay called out the child's name several times, and was shocked to hear her voice from inside the deep hole.

Rescue teams arrived and lowered a camera to check on Tasa Mo-ei's condition, finding her still alive and responsive.

They filled the narrow space with oxygen from tanks and commenced with the mission widening the well's hole first using excavators, and later by hand.

The responders said they were operating under low visibility, and were careful of collapsing the ground.

The rescue is ongoing as of 7 am local time on February 7.