Qatar has $340 billion in reserves including holdings of its sovereign wealth fund that could help the Gulf country to weather the isolation by its powerful Arab neighbours, central bank governor Sheikh Abdullah Bin Saoud al-Thani told CNBC.

"This is the credibility of our system, we have enough cash to preserve any..kind of shock," he told the news channel in an interview published early on Monday on its website.

Al-Thani said the central bank has $40 billion in reserves plus gold, while the Qatar Investment Authority has $300 billion in reserves that it could liquidate.

"Qatar has already had a good and unique system. We have laws established against all these kinds of terrorists ," al Thani told CNBC. "We work with the IMF (International Monetary Fund) and other institutions to establish our laws and audits and reviews."

"We have no challenges, we welcome those to review all our books, they are open," he added. Al-Thani said while the central bank has noticed fund outflows from some non-residents, the amounts weren't particularly significant.

"There is more coming in," he said, confirming that inflows are exceeding outflows.

He said long-term contracts in the gas and oil sectors were not seeing any disruptions.

Rating agency Moody's Investors Service earlier this month changed the outlook on Qatar's credit rating to negative from stable, citing economic and financial risks arising from the ongoing dispute between Qatar and the Saudi-led alliance.

Despite the market ructions, economists say Qatar, the world's top liquefied natural gas exporter, has taken a number of measures such as a planned boost in gas output and new transport routes to weather the crisis.

Starting from June 5, Bahrain, Comoros, Egypt, Maldives, Mauritania, Saudi Arabia, United Arab Emirates, Yemen's internationally backed government and one of Libya's three governments have cut off diplomatic ties with Qatar over accusations that the Gulf nation funds militant groups – charges Doha calls baseless.

Several other Muslim nations also downgraded their diplomatic ties with Qatar.

The Saudi-led anti-Qatar axis issued an ultimatum earlier, including demands Qatar shut down a Turkish military base in Doha, shutting Al Jazeera and curbing ties with Iran.

Qatar rejected the 13-point list of demands its neighbors made for lifting their sanctions.