The mission to save the child has triggered an outpouring of public support as rescuers struggle with the challenge of bringing heavy equipment up steep access roads and reaching the toddler safely.

The lead engineer overseeing the operation, Angel Vidal, said rescuers were "incredibly motivated" to reach the boy as soon as possible.

"We're not bothered by the hours, the tiredness or the lack of sleep," he said on Saturday.

"We are hopeful that we will reach him as soon as possible and bring him back to his parents."

The boy, Julen, fell into the 25cm-wide and 100m-deep borehole as his family walked through a private estate in Totalan, Malaga.

Officials have been unable to find signs of life but say they are working on the basis that the child is still alive.

Video footage shot by firefighters and released by Spanish broadcaster Canal Sur shows a blockage around 70m into the well which has prevented rescue services from sending food or water to the child.

Trucks brought drilling equipment and giant pipes to the site on Friday.

Drilling of the first of two tunnels that will be made to reach the boy will take around 15 hours, officials said.

Once the first tunnel is completed, rescuers will begin working by hand to construct a second shorter tunnel to reach the area where the boy is trapped, which will take a further 20 hours.

Australian Associated Press