* Petroamazonas is Ecuador's largest oil producer
* Ecuador's overall output also seen up 4 pct in 2013
* Manager says company to invest $2.23 billion in 2013 (Adds details, quotes)
By Jack Kimball
BOGOTA, Jan 30 (Reuters) - Ecuador's state-run oil company Petroamazonas expects crude output to increase 4 percent in 2013 to an average of 325,000 barrels per day (bpd), its General Manager Oswaldo Madrid told Reuters on Wednesday.
Petroamazonas is Ecuador's largest oil company and its output accounts for about 60 percent of the crude produced in the OPEC-member country.
"The (output) increase will come mainly from work that Petroamazonas will carry out in the fields that we just received from Petroecuador," Madrid said in an interview in Bogota.
The company currently produces an average of 312,000 bpd.
Starting on Jan. 1, Petroamazonas took over the fields of state-run company Petroecuador and became the Andean country's upstream firm while Petroecuador now runs three refineries and a key oil pipeline.
The main drivers of output growth this year would come from the oil fields of Oso, Shushufindi and Auca, Madrid said.
Petroamazonas plans $2.23 billion in capital expenditures in 2013, up from $1.4 billion in 2012, mainly to consolidate its operations after becoming the state upstream company, Madrid said.
"It's important that we invest this year for the coming years," he said.
Ecuador is the Organization of the Petroleum Exporting Countries' smallest member and its economy is heavily dependent on oil exports.
The country's total average crude output is likely to increase to 524,000 bpd in 2013 and to 540,000 bpd in 2014 compared with 504,000 bpd last year, Madrid said.
After taking office in 2007, Ecuador's leftist president, Rafael Correa, introduced reforms to increase state revenue from the oil industry, and since then foreign oil companies have not invested in new projects.
Higher crude prices have allowed Correa to increase social spending in recent years, which in turn has boosted his popularity among the country's low-income majority ahead of a presidential election scheduled for February.
Ecuador has launched a licensing round for 13 blocks while Petroamazonas wants to tap three blocks, which are in the southeast, near the border with Peru, far from the northern Amazon regions where most of Ecuador's crude is extracted.
Petroamazonas' areas may have resources of more than 300 million barrels, Madrid said.
Total investment for all the blocks could reach $1.8 billion, he said, higher than a government estimate of around $1 billion.
"(The investment) may begin in 2014. This is a process that's going to take several years ... until those fields start producing," Madrid said. (Reporting By Jack Kimbal; Writing By Eduardo Garcia; Editing by Gerald E. McCormick, Maureen Bavdek and Bob Burgdorfer)