Moody's Investors Service said it has upgraded the long-term deposit and debt ratings of seven banks in China to 'A1' from 'A2', following the rating agency's earlier upgrade of China's long-term foreign currency sovereign rating.

The seven banks are Industrial and Commercial Bank of China (ICBC), Bank of China, China Construction Bank (CCB), Agricultural Bank of China, China Development Bank (CDB), Export-Import Bank of China and HSBC Bank (China) Co.

In a statement, Moody's said the upgrade of the four state-controlled commercial banks - ICBC, Bank of China, CCB, Agricultural Bank of China - reflects its view that the government is likely to maintain majority control and continue to provide very strong implicit support to these banks.

Their bank financial strength ratings remain unchanged, Moody's said.

The upgrade of the two policy banks - CDB and Export-Import Bank - is in line with the sovereign rating action because they are government related issuers and fully owned by Beijing, Moody's said.

The rating agency added that the upgrades also reflect its view that both will be fully supported by the government because of their policy bank status.

Moody's also said HSBC China's ratings are no longer constrained by China's sovereign ceilings.

The rating agency earlier raised the Chinese government's long-term foreign currency bond rating to 'A1' from 'A2'.