The specialist insurance market said yesterday that claims from the catastrophes were not expected to make a "material impact" on its capital and it should not have to dip into its central fund - the market's emergency reserve of capital.
Chief executive Richard Ward said: "The Lloyd's market is as well capitalised as it has ever been and, while claims from all three events could still evolve over time, the market's total exposure is well within the worst-case scenarios we model and prepare for."
Lloyd's estimated net claims from the Japanese earthquake and tsunami at $1.95bn (1.2bn). The earthquake that devastated Christchurch, New Zealand's second largest city, is set to cost it $1.2bn, while the bill for January's flooding in Australia will be about $650 million.
The preliminary estimates draw on market share analysis, the application of modelling techniques, a review of contracts in place and estimates from each syndicate.
Yesterday's figures compare to industry losses of $30bn for Japan, $9bn for New Zealand and $5bn for Australia.
Lloyd's share of the bill for the Japanese disaster is smaller, as the country has a better coverage from domestic insurers.
The magnitude 9.0 quake and tsunami that struck Japan's north-eastern coast on 11 March left 25,000 people dead or missing. More than 100,000 remain in temporary shelters.
The industry cost estimate does not include life assurance and the public sector component of the Japan Earthquake Reinsurance.
Ward said yesterday that the spate of disasters, compounded by recent tornadoes in the US, would lead to higher insurance premiums.
He said: "We expect to see a firming of rates as a result of this first quarter and the recent tornadoes in the United States." The death toll for the series of more than 200 tornadoes that ripped across six states is above 300, while US officials are still tallying how many homes were destroyed.
The Christchurch earthquake killed at least 169 people on 22 February. Flooding in eastern Australia has killed 35 people since November, damaged or destroyed more than 35,000 houses and damaged crops and coal mines.
Lloyd's is a society of corporate underwriters and wealthy individuals that make insurance transactions through 44 managing agents and 62 syndicates.
The 323-year-old institution made 2.2bn last year despite paying out for disasters including a major earthquake in Chile and the explosion on BP's Deepwater Horizon oil rig. The figure was down 43 per cent on 2009, a year that witnessed fewer natural disasters.