(Adds Reuters poll results in paragraph one, month-on-month decline in paragraph two, mining output in paragraph 5)
LIMA, May 15 (Reuters) - Peru's economic output grew 0.71 percent in March compared with the same month a year earlier, beating expectations in a Reuters poll for a contraction of 0.5 percent, the government's national production indicator showed on Monday.
It marked the smallest annual gain since November 2014, the national statistics institute Inei said. Economic output also fell 0.4 percent in March, compared with February, the third straight month-on-month decline.
On Friday, the Economy Ministry said in a statement it was expecting year-on-year growth of around 0.5 percent in March.
Heavy rainfall and flooding in the country's northern regions were major factors curbing growth, Inei director Anibal Sanchez Aguilar said.
The mining sector fell 2.7 percent in March, compared with a year earlier, due to the unfavorable weather and a three-week strike at the Andean nation's biggest copper mine, Freeport-McMoRan Inc's Cerro Verde, he added.
Peru is the world's second-largest copper producer.
Economic output grew 2.08 percent in the first quarter of 2017 compared with the same period last year, Inei added. (Reporting by Luc Cohen and Teresa Cespedes; Editing by Chizu Nomiyama and W Simon)