A 10-year-old girl has been decapitated by a crocodile in a Philippine lake after it knocked over her canoe.

The girl and a classmate were on their way to their floating school on Mihaba Lake when the seven metre crocodile hit the boat and caused it to capsize.

Rescuers found the girl's headless body floating on the lake yesterday.

Her classmate was rescued by a man escorting the pair in another boat.

Roel Hipulan from the group that runs the school said it was a monster crocodile.

He said saltwater crocodiles, some bigger than a bus, are known to inhabit the lake, though attacks are rare.

"The crocodiles have become aggressive," he said.

The lake's waters have been swollen for the past several months, causing fish to scatter to others parts.