Authorities in Peru have declared that the intense rains, overflowing rivers, mudslides and flooding being experienced in the country are the worst seen in two decades, with the death toll since the beginning of the year having hit 72.

Key points: Death toll has risen to 72 since the beginning of the year

Death toll has risen to 72 since the beginning of the year Prices have shot up 5 per cent across the country

Prices have shot up 5 per cent across the country Presidents of Chile, Bolivia and Venezuela have offered help

The highly unusual rains follow a series of storms that have struck hard along Peru's northern coast, with voracious waters inundating hospitals and leaving some small villages isolated.

The storms are being caused by a warming of the surface waters in the Pacific Ocean and are expected to continue for another two weeks, with the disaster affecting more than half the nation.

The Peruvian Government said that 374 people were killed in 1998 during a similar period of massive rains and flooding blamed on the El Nino climate pattern.

On Saturday, Prime Minister Fernando Zavala updated the number of dead from the latest flooding to 72.

Residents salvage belongings from their destroyed home in Huachipa in the capital Lima. ( Reuters: Mariana Bazo )

Fumigation targets dengue-carrying mosquitoes

The rains have overwhelmed the drainage systems in cities along Peru's Pacific coast and the health ministry has started fumigating around the pools of water that have formed in the streets to kill mosquitoes that carry diseases like dengue.

Peru's capital city, Lima, has been without a water service since the beginning of the week.

The Government has deployed the armed forces to help police control public order in the 811 cities that have declared an emergency.

"The prices for lemons have gone up, as well as for potatoes and cooking oil," said Sara Arevalo, a mother of five who was shopping at a market in northern Lima.

The Government has acknowledged that prices have shot up some 5 per cent because of the flooding.

Survivors of a flood receive food after torrential rains caused flooding and widespread destruction in Huachipa, Lima. ( Reuters: Mariana Bazo )

Inmates escape juvenile detention centre

In the Lambayeque region, 22 inmates at a juvenile detention centre took advantage of the rains to escape.

Rains flooded a cemetery in the city of Trujillo with the waters carrying bones through the streets.

Even in Lima, where a desert climate seldom leads to rain, police had to help hundreds of residents in an outer neighbourhood cross a flooded road on Friday, by sending them one-by-one along a rope through choppy waters.

The muddy current channelled down the street after a major river overflowed. Some residents left their homes with a single plastic bag carrying their belongings.

The presidents of Chile, Bolivia and Venezuela offered to send help to Peru.

AP