Insurance losses from a spate of US tornadoes early last month are continuing to climb, with the latest estimates saying the bill could be as high as $US6 billion ($5.6 billion).

Risk modeller RMS released this figure last week. It is comparable to rival AIR Worldwide’s estimates of up to $US5.5 billion ($5.17 billion) in insured losses.

However, the cost of severe tornadoes that lashed the southern parts of the US from April 22 to April 28 have not yet been included.