* GNPC says loan will save Ghana money
* Politicians call for parliamentary approval
* Loan oversteps constitutional due process-think tank (Updates with quotes, context)
By Kwasi Kpodo and Simon Falush
ACCRA/LONDON, Nov 14 (Reuters) - Ghana National Petroleum Corporation (GNPC) is in talks with commodities trader Trafigura and banks for a $700 million five-year loan at 4.43 percent to fund oil and gas projects, GNPC and a source close to the deal said on Friday.
The deal would be Trafigura's first in Ghana and GNPC said it would be funded through its mandated share of national oil export revenue rather than using oil as collateral.
GNPC is a key player in a country where oil exports are the second biggest source of revenue and it is seeking $1 billion to become an independent operator.
GNPC cannot fund itself entirely through public sources and the loan would save money in the long term, GNPC said in a document prepared for the deal and seen by Reuters.
"GNPC has to be prudent and build up capital for its growth. This is normal commercial practice. No serious company lives from year to year," it said. It did not name the banks involved.
GNPC is in talks with Offshore Cape Three Points (OCTP) partners for a $493 million gas pipeline and receiving facility and would pay 22 percent interest were it not for the new loan.
Ghana is on course to produce around 105,000 barrels of oil per day in 2014 from its offshore Jubilee field, GNPC said. It expects $15-$20 billion in oil investment over the next decade.
Britain's Tullow Oil is the lead stakeholder in Jubilee while GNPC holds a 13.6 percent stake.
GNPC said it would not go to parliament for approval but politicians from the ruling party and the main opposition told Reuters any loan needed scrutiny in part because it exceeded the government's annual allocation to GNPC.
"We have given them the money for the year so if they are asking for $700 million they need to come and explain to us the need for this huge further expenditure," said Kobina Hammond, energy spokesman for the opposition New Patriotic Party.
Ghana discovered oil in 2007 and many groups scrutinise its financing out of concern that oil money could corrupt officials and distort the economy it has done in other countries.
The announcement comes at a sensitive time ahead of the annual budget and during talks with the International Monetary Fund for financial assistance to restore fiscal balance in a economy that has seen rapid growth on its commodity exports.
Any loan without parliamentary approval would overstep constitutional and legal due process, said the influential African Centre for Energy Policy, which called for a suspension of the loan. (Additional reporting and writing by Matthew Mpoke Bigg; Editing by David Evans)