Brydens, which specialises in personal injury claims among other practice areas, was taken to court by a former client who wanted the firm to hand over an itemised bill for work it did for him in a District Court case.

The firm had provided Tan Thanh Le, a native Vietnamese speaker, with a lump sum bill for $304,688 but he wanted a breakdown to give to a costs assessor to determine the fairness and reasonableness of the fees.

Brydens had refused to provide an itemised bill on the basis Mr Le had asked for it after a 12-month time limit had expired. The firm also said it had lost his files, which was accepted by the Supreme Court.

In March Supreme Court justice Monika Schmidt rejected Brydens' arguments and ordered the firm to hand over an itemised bill.

On Friday, Justice Schmidt delivered a scathing second judgment ordering Brydens to pay Mr Le's costs of pursuing them in court. The costs order was made on an indemnity basis, which is higher than the costs usually awarded in litigation and would cover his entire legal bill.

"The approach which Brydens pursued in these proceedings in the circumstances, I consider, was entirely cynical," Justice Schmidt said.

Justice Schmidt said the firm was aware Mr Le had a "limited command of English" and should have consented to his application to have the costs assessed rather than fighting him in court.

She said Brydens had relied on "hopeless technical points" in fighting his application and a separate Supreme Court decision in August 2015 had already rejected Brydens' arguments on the same issues.

"The result of Brydens' failures to abide by its statutory obligations was that Mr Le was unnecessarily put to the costs which he has incurred in these proceedings," Justice Schmidt said.

A solicitor at Brydens gave evidence in February that Mr Le's file had been lost sometime after December 2014 but no evidence was given by the firm's principal, Lee Hagipantelis.

In her earlier judgment in March, Justice Schmidt accepted the file had been lost but said she was "satisfied that an inference must be drawn that the evidence which Mr Hagipantelis could have given ... would not have assisted Brydens' case".

Brydens acted successfully for Mr Le in a District Court case after he was injured in a forklift accident at work. He was awarded more than $1 million in compensation, although a significant amount had to be repaid by him to his workers' compensation insurer.

The firm sent Mr Le the lump sum bill in July 2013. He changed solicitors in mid-2014 and the new firm requested Brydens provide an itemised bill because the District Court had ordered Mr Le's employer to cover his legal costs and it was disputing the amount.