Barclays said it is considering raising capital and other options as part of the country's plan to strengthen balance sheets across the sector.

"Barclays confirms that it is considering a number of options, including capital raising, relating to the industry wide commitment to increase tier 1 capital in the sector by an aggregate £25 billion," the bank said.

Barclays, the country's second biggest bank, would boost its capital by offering existing investors the chance to take preference shares or other instruments, Reuters reported, citing people familiar with the matter.

Earlier this year, it raised £4.5 billion, mainly by attracting several big outside investors, rather than through a conventional rights issue.

Its biggest shareholders now include Qatar's sovereign wealth fund, state-owned China Development Bank, Singapore's Temasek TEM.UL and Japanese bank Sumitomo Mitsui.

Barclays needs about £5.5 billion of extra capital, analysts at Bernstein estimate. Deutsche Bank analysts estimated it needs £2.5 billion.

The government is offering up to £25 billion for banks to boost their capital, but said there is no obligation on banks to use the government funds and they can raise capital privately. Capital needs to be boosted by the end of the year.

"Barclays will update the market on its plans in accordance with this timetable," the bank said.