A legal expert has warned of extensive shortcomings in proportionate liability legislation across Australia.

Queensland barrister Richard Douglas told the Australian Insurance Law Association’s annual Geoff Masel Lecture that jurisprudence around proportionate liability has developed at a snail’s pace since the release of the Ipp report on the matter 16 years ago.

Proportionate liability allows courts to apportion responsibility for damages claims among wrongdoers.

Mr Douglas blames drafting complexity for the shortcomings, with disparate drafting yielding varying jurisprudence.

Procedural provisions to identify those at fault are cumbersome and readily circumvented, he says, and apportionment is often unpredictable and unsatisfactory.

The effect of these shortcomings will remain in the system for some time, because any legislative amendments would be prospective, not retroactive, Mr Douglas says.