PUEBLA, MEXICO (AFP) - A giant sinkhole that is expanding by dozens of metres each day has alarmed residents in a rural area of central Mexico, where it is threatening to swallow a house.

When the Sanchez family heard a loud crash on Saturday (May 29), they first thought that it was a lightning strike.

But they soon discovered that the ground had collapsed just metres from their home in a field in Santa Maria Zacatepec in the state of Puebla.

The hole, which is full of water, was about 30m wide by Sunday.

It rapidly grew to 60m by Monday and, was around 80m on Tuesday, the authorities said, coming perilously close to the house of the Sanchez family, who fear they will be left homeless.

"We have nothing. We're not from here. We have no relatives. We're alone," Mr Heriberto Sanchez, originally from the south-eastern state of Veracruz, told the media.

Scientists and the authorities are considering hypotheses, including a geological fault or variations in the soil's water content, as possible causes.

As the sinkhole has grown, large chunks of earth have continually broken away from the rim, scaring off onlookers approaching a security cordon set up by the authorities.

In a video posted on social media, two men are seen approaching the hole shortly before it expands suddenly, forcing them to run to safety.

"It will grow until nature decides, when the water stops exerting pressure," Puebla state governor Miguel Barbosa said.

"The important thing now is public safety," he said, adding that the authorities would compensate those affected.