By Davide Barbuscia and Tom Arnold

DUBAI (Reuters) - Gulf governments are increasingly turning to export credit agencies (ECAs) to finance billions of dollars of infrastructure projects as low oil prices squeeze liquidity in the region.

Bankers say that since oil prices fell more than two years ago, eroding state revenues and drying up funding from local and international banks, borrowers are considering ECA finance for everything from airports to oil refinery expansion.

The extent of its use in the future is difficult to predict, but at least a portion of the estimated $2 trillion of projects planned in the Gulf Cooperation Council are likely to require ECA involvement.

"As the credit environment tightened, so did the ability of banks to take large tickets without the benefit of credit risk mitigation. As a result, the drivers of infrastructure spends, such as sovereigns and large public sector entities, are evaluating alternate modes of financing, including ECA financing," said Yusuf Ali Khan, managing director and trade head, Middle East, North Africa, Pakistan and Turkey at Citigroup.

ECA-backed financing structures enable the export and supply of domestic goods or contractors through loan guarantees, or in some cases even direct lending, from the agencies to an overseas borrower.

"ECA funding is not only a matter of credit risk mitigation, it also enables projects to access a much larger pool of liquidity," said Alarik d'Ornhjelm, head of structured trade and export finance, Middle East and Africa, at Deutsche Bank.

Projects in Dubai such as expanding Al Maktoum International Airport, destined to be the world's largest when complete, or the expansion of the red line metro to the World Expo 2020 site, will both require debt funding backed by guarantees from international ECAs.

Also in Dubai, the government is expected to need roughly $7 billion for projects linked to the Expo 2020, and ECA-backed financing is likely to represent a large part of this.

Marco Ferioli, head of UAE and MENA at the Italian export credit agency SACE, confirmed to Reuters that ECA financing will have a role in projects related to Expo 2020, and that SACE will be available to support Italian firms involved. SACE has also expressed interest in providing a credit line worth 1 billion euros ($1.1 billion) to support Italian firms involved in expanding the Al Maktoum airport, he said.

Beyond the UAE, a clean fuels project, promoted by the Kuwait National Petroleum Company, will require an ECA-backed loan of over $5 billion, and in Saudi Arabia the development of a six-line Riyadh metro system – expected to cost more than $20 billion – will also use ECA-backed debt.

(Editing by Ruth Pitchford)