Motor Accidents Authority of NSW v Mills  NSWCA
NSW Court of Appeal1
A Court or Claims Assessor does not have the power to bind a
Medical Assessor on the issue of causation.
A certificate under Pt 3.4 of the Act of the degree of
permanent impairment of the injured person as a result of the
injury caused by the motor accident is conclusive evidence of the
degree of that permanent impairment and its causation by
the motor accident.
Mr Mills alleged that he injured his back in a motor accident
which occurred on 10 April 2000. This was disputed by the Nominal
Defendant and the matter was referred to MAS. In December 2003 a
MAS Assessor made a finding that no back injury was caused by the
District Court of NSW – Coorey DCJ
During the course of the trial, the Court reached a finding that
the back injury was caused by the accident and referred the
question of impairment back to MAS for further assessment pursuant
to s 62 of the Act. The order (which was made prior to October
2008) was in the following terms:
"The Court refers only the
question of the extent of the plaintiff's whole person
impairment and not the question of whether or not that impairment
(or injury giving rise to it) was caused by the accident, the
subject of these proceedings".
An application by MAA to intervene was subsequently granted but
the Court declined to vary the order.
Court of Appeal – Giles JA, Tobias JA and Handley
The MAA sought relief in the nature of certiorari on the basis
of a jurisdictional error. It contended that the Court had no power
to make the referral to MAS on terms which excluded the issue of
Giles JA, with whom the others agreed, concluded:
"74. In my opinion, in doing
so, his Honour went beyond the power conferred by s 62(1). That
comes from the terms of s 62(1) and its place in the scheme as
described in the preceding paragraphs. S 62(1) spoke of referral
again of "a matter referred for assessment under this
part". The original matter referred had both the elements of
causation and of degree of permanent impairment. The section should
be understood in accordance with its terms, that is, referral of
that matter again. In accordance with the scheme, both elements
were for the Medical Assessor, and the Court could not decide them.
The Judge's finding made for the purpose of deciding that there
should be referral again under s 62(1) did not bind the parties in
the assessment, and he could not make an order binding on the
parties to prevent the Medical Assessor determining the issue of
In answer to Mr Mills' submission that it was inappropriate
for a Medical Assessor to make binding conclusions on causation
which could well involve non medical issues including the credit of
the injured person, the Court gave the following response:
"79. The submissions face
the difficulty that the degree of permanent impairment as a result
of the injury caused by the motor accident (s 58(1)(d); s 131) was
unequivocally for the Medical Assessor, including the element of
causation. That was accepted in Pham v Shui at  and it was
correctly so held in Ackling v QBE Insurance (Australia) Limited
 . The legislature accepted such constraints as there may
have been on investigation or being provided with materials, and
dealt with that amongst other possible deficiencies in a medical
assessment by what I have called the safety valve of a Court's
power to refer again. The legislature having chosen to provide the
threshold in s 131 of the Act and brought it within the scheme for
medical assessment under Pt 3.4, the possibility of anomaly was met
by the safety valve".
On the face of it, the prohibition on a Court or CARS Assessor
of binding a MAS Assessor on causation may give rise to injustice.
The Medical Assessor has, after all, limited scope for testing a
claimant's credibility and fairly evaluating competing evidence
as to the cause of impairment. However, the legislature created a
safety valve in the form of the power to refer again under s
62(1)(b). Relevant evidence and submissions can be put to MAS as
part of the referral. Such a referral is not constrained by the
need to demonstrate deterioration or additional relevant
information within the confines of s 62(1)(a). The availability of
that mechanism should not be overlooked.
Whilst it was not essential to their determination in this case,
the Court of Appeal has given a strong indication that the
conclusiveness of a certificate on the issue of causation is now
settled. This would appear to apply equally to certificates issued
under the post October 2008 scheme.
1 Giles JA, Tobias JA, Handley AJA
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