The heavy economic reliance on oil and gas for revenue means Oman is more exposed to economic risk that its peers, Moody's Investors Service said.

Moody's assigned Oman a Baa1 credit rating, meaning its economy is subject to moderate risks and may carry some speculative characteristics. The ratings agency said Oman's finances may be better off next year than last year, when oil was trading in a market clearly favoring the supply side.

"Having said that, Oman's heavy economic and fiscal reliance on the oil and gas sector represents a key credit risk," the ratings agency said in an emailed note.

In January, the World Bank said some oil exporters in the region could see GDP growth of 6.2 percent this year. By May, Moody's was warning the drop in crude oil prices, off more than 50 percent since the middle of 2014, has undermined the economy and finances for members of the Gulf Cooperation Council: Saudi Arabia, Kuwait, the United Arab Emirates, Qatar, Bahrain and Oman.

The May report noted that governments like Bahrain, Oman and Saudi Arabia, which have faced human rights pressure, may be dealing with complex underlying social issues that may impede the implementation of economic policy reforms.

In its most recent note, Moody's said Oman was suffering a steeper financial decline than its peer economies in the GCC because of its dependence on oil and natural gas. Hydrocarbons accounted for nearly 70 percent of total exports, while oil and gas revenues accounted for almost 90 percent of total government revenues in the five years ending in 2015.

Last month, the government issued $500 million worth of trust certificates, bonds backed by other assets. Moody's in its profile said that exposed bond holders to further credit risk.

Oman is the largest regional oil and natural gas producer that's not a member of the Organization of the Petroleum Exporting Countries. Total oil production is around 1 million barrels per day. The country exports around 375 billion cubic feet of natural gas per year and, using liquefied natural gas, is a key supplier to the Asian economy.