Herds of wild elephants have destroyed more than 50 hectares of paddy rice in some farms near a national park in central Tanzania, local press reported Thursday.

The elephants roaming out of the Mikumi National Park invaded the farms, causing huge losses to the staple and cash crops of farmers in that region, the Daily Times newspaper said.

"I have invested a lot of money and energy there in the fields only to find everything destroyed (by elephants)," farmer Dikupatile Edwini was quoted as saying.

There have been several reports in the past six months about elephants harassing and destroying farm crops.

The number of wild elephants has been on the rise since 1990 thanks to protective measures in the east African nation.

There were some 2 million heads of elephants in 1970 but the figure declined to 35,000 in 1990.

The number has rebounded to between 450,000 and 600,000 heads now, with the largest herd in the Selous Games Reserve, where there are more than 60,000 heads of elephants.