Rating agency AM Best says the recent string of natural catastrophes has yet to dent the central assets at Lloyd's.

The agency said Lloyd's estimates it will be hit by £1.2bn in claims from the Japan earthquakes, £750m from the New Zealand earthquakes and £406m from the flooding in Australia.

"Although these loss estimates remain subject to considerable uncertainty, current figures do not exceed AM Best’s expectation for Lloyd’s exposure to such events, and central capital is unlikely to be affected." the agency said.

AM Best made the comments as it affirmed its A financial strength rating for Lloyd's with a stable outlook.

The agency said Lloyd's capitalisation is expected to remain strong in 2012. It pointed out that central assets are growing (up 8% to £3.05bn in 2010), while the exposure of the assets to insolvent members is shrinking as run-off liabilities decline.

AM Best said that Lloyd's risk-based approach to setting members' required capital levels, as well as its close monitoring of syndicate performance, should reduce the risk of material drawdowns on the central fund from future member insolvencies.

However, the agency added that a smooth transition to Solvency II in 2013, including approval of its internal capital model, is "crucial" if Lloyd's is to maintain its capital efficiencies.