The move is a response to daily brownouts of 5-8 hours that are hurting the local economy, presidential adviser for Mindanao Jesus Dureza said.

Arroyo's spokesman, Gary Olivar, said the declaration would allow local governments to tap their calamity funds to generate additional power supply.

Mindanao, the country's food basket, is experiencing severe power shortages of more than 700 MW due to the dry spell brought by the weather phenomenon El Nino, drying up dams that run hydropower plants.

A month ago, the daily power shortage was less than 200 MW.

Under a state of calamity, the government can hasten deals to deliver electricity, such as leasing generation sets, transfering power barges and tapping power supply generated by private firms.

"This declaration will take effect soon until July, when the rains come and we expect the hydropower plants to generate the necessary electricity there," Olivar added.

Agriculture is being hit hard by a dry spell that has resulted in farm losses amounting around 7 billion pesos ($152 million) as of last month, the government had said.