"We are collecting pets from backyards of houses and taking them to the municipal gym, where it will be easier to feed them," said Macarena Zanelli, head of the veterinary faculty of the University of Saint Thomas in the southern town of Puerto Montt, where many evacuees are being sheltered.

"We are finding them very hungry and thirsty, afraid and sticking close to their homes," she added.

Zanelli said some pets would be transported to Puerto Montt at the request of their owners, who were evacuated in naval ships from the town which is only accessible by air or sea.

Other animals would be looked after in Chaiten itself by the vets.

Ash from volcano, which is 760 miles (1,220 km) south of the Chilean capital Santiago, has contaminated ground water supplies and experts say it could be weeks or months before residents can return.