The ABI and the British Chambers of Commerce (BCC) have clashed over a BCC survey on the impact of the employers' liability (EL) crisis.
The ABI has taken issue with the BCC's suggestions that insurers are offsetting their losses in other classes of business by loading EL premiums.
It also rejects the BCC's criticism that insurers are acting in an anti-competitive manner by refusing to write cover for good risks.
The survey found that over 6% of businesses and 9% of manufacturers had been refused insurance cover.
It also found that 20% of manufacturers had seen premium increases of between 50% and 100%.
BCC director general David Frost said: "We accept that insurers must seek a reasonable rate of return. However, we do expect the rate of return to be limited by effective competition.
"We do not expect losses from unrelated forms of insurance, or other sectors of industry, to be recouped through increases in liability premiums."
An ABI spokesman said: "We refute suggestions that insurers are trying to offload losses. The premiums being charged have to reflect risk."
Regarding suggestions of anti-competitive behaviour, the spokesman said: "We are not aware of a widespread problem of companies not getting cover."