42 This appears to be the effect of the case law. In Forstaff Blacktown Pty Limited v Brimac Pty Limited and Anor [2005] NSWCA 423, Hodgson JA said:
2 In my opinion, the requirement in para.(d) of s.151Z(2) of the Workers' Compensation Act that the amount of the contribution that a person other than the worker's employer is entitled to recover from the employer "is to be determined as if the whole of the damages were assessed in accordance with the provisions of Division 3 as to the award of damages" must be read in conjunction with pars.(a) and (c) of s.151Z(2), which refer to proceedings that the worker takes or is entitled to take against that person; and par.(d) must thus be understood as referring to a hypothetical assessment of damages in those proceedings . Where, as in this case, those proceedings against that person were taken by the worker after 27 November 2001, par.(d) must be taken as referring to a hypothetical assessment of damages in proceedings taken after 27 November 2001. That view is consistent with Clout Industrial Pty. Ltd. (In Liquidation) v. Biaida Poultry Pty. Ltd. [2004] NSWCA 89, 61 NSWLR 111.
3 This means that contribution recoverable under par.(d) will be nil if the injury did not result in a degree of permanent impairment of the injured worker that is at least 15%; and if the contribution recoverable under par.(d) is nil, then par.(c) requires that the damages that the worker may recover from the person other than the employer are to be reduced by the whole of the amount of the contribution the person would have been able to recover from the employer but for the effect of par.(d). This gives rise to questions as to who bears the onus of proof.
4 In a case such as the present, where the contribution proceedings against the employer are heard together with the proceedings brought by the worker against the person other than the employer, it is clear in my opinion that, if it is not proved by someone in the proceedings that the injury resulted in a degree of permanent impairment of 15% or more, the contribution claim will fail under par.(d); and if the person making the contribution claim proves that the employer would otherwise have been liable to contribute a certain percentage, the worker's damages under par.(c) will (for consistency) have to be reduced by that percentage. Thus, there will as a practical matter be an onus on the worker to prove that the 15% threshold is passed. If the worker does not prove this, the person making the contribution claim may achieve a reduction in damages recoverable by the worker without having to prove that the 15% threshold is not passed, albeit at the expense of liability for the employer's costs of the contribution proceedings.
5 However, in my opinion the position concerning onus of proof may be different if the proceedings brought by the worker against the person other than the employer are heard on their own, in the absence of or prior to the hearing of contribution proceedings brought by that person against the employer. It seems to me that that person, as defendant in the proceedings brought by the worker, must have the onus of proving the elements set out in par.(c) in order to obtain any reduction of damages: that is, there will be no reduction of damages as discussed in par.[3] above unless the defendant proves that it would, but for Part 5 of the Workers' Compensation Act, be entitled to recover an amount from the employer and that the contribution actually recoverable is nil. In those circumstances, it seems to me that the defendant would have to prove that the injury did not result in a degree of permanent impairment of 15%; although I accept that it may be possible to do this by way of inference from the general evidence in the case, where the worker has not sought and failed to obtain the certificate required to establish this degree of impairment. In that respect, I think the position may be different from that supported by McColl JA; although it is not necessary finally to determine that matter in these proceedings. [My emphasis]