UPDATE 1-Ecuador's economy grows 4.7 pct in 3rd quarter

* Economy forecast to grow around 5 percent in 2012

* Strong growth seen helping president's re-election bid

QUITO, Jan 9 (Reuters) - Ecuador's economy expanded 4.7 percent in the third quarter of 2012 compared with the same period the year before, the central bank said on Wednesday.

High oil revenues have allowed leftist President Rafael Correa to boost state spending on infrastructure and welfare, which has fueled economic growth over the past few years. The economy expanded 8 percent in 2011 and 3.3 percent in 2010.

The Ecuadorean government has forecast economic expansion in 2012 of around 5 percent.

According to economic officials, growth in 2013 will be affected by the global economic slowdown and the idling of the country's largest refinery, Esmeraldas, which is scheduled to go offline for several months for an overhaul.

Central bank data shows that quarterly growth has been slowing since its peak of 9.1 percent in the third quarter of 2011.

Ecuador is OPEC's smallest member and benefited from high crude prices last year. Tax revenues rose 17.8 percent to $11.3 billion, which allowed the government to increase social and infrastructure spending ahead of an election in February.

Polls show that Correa is the clear favorite to win the election, helped in part by the good state of the economy.