Authorities have confirmed the 10-year-old Vietnamese boy who fell into a hollow concrete pillar on New Year's Eve has died.

Thai Ly Hao Nam fell into the 25cm (12-inch) wide shaft of the pillar at a construction site while searching for scrap metal.

Rescuers in the province of Dong Thap tried to raise the pillar from its 35-metre deep hole and cut the boy out. Authorities are now working to recover his body for burial.

Doan Tan Buu, deputy chief of the southern Vietnam province said there was not enough oxygen for him to survive and that he had suffered multiple injuries.

"We had prioritised the rescue of the boy. However, the conditions mean it is impossible the boy has survived," he said.

The boy was heard crying for help after he fell into the pillar, but rescuers said they received no response from him when they lowered a camera into the shaft on Monday.

They had been removing mud and water in an attempt to bring the pillar up, and oxygen was pumped into the pillar to help the boy breath.