Reynolds Porter Chamberlain (RPC) has warned insurers to write exclusion clauses for toxic mould into their policies.
The law firm was reacting to research results that showed that cases could affect one in four UK buildings.
The firm also said surveyors' PI premiums may rise as a result of the findings.
The research, carried out by the Royal Institution of Chartered Surveyors and to be published this November, suggests toxic mould could be present in 25% of UK properties.
Toxic mould is believed to cause cancer, asthma, bronchitis and some allergies.
RPC partner Robert Hogarth said: "The costs associated with surveying and removing toxic mould are likely to be significant.
"Insurers that have not written exclusion clauses for toxic mould into policies should consider doing so."
Hogarth said: "Whether insurers or landlords pay for the clean-up of commercial buildings could be a potential source of conflict."
The discovery of toxic mould in the UK could also result in a significant rise in surveyors PI premiums.
"Surveyors could be sued for diminution of value if they fail to detect harmful contaminants," Hogarth said.