Laws rushed through NSW Parliament to validate a series of corruption findings will be challenged on constitutional grounds as a group of wealthy businessmen renew their legal bid to have findings against them overturned.

The NSW Court of Appeal heard on Friday that mining mogul Travers Duncan and others were pressing ahead with their challenge to findings that they acted corruptly by concealing the involvement of the Obeid family in a coal tenement.

Travers Duncan is pressing ahead with a challenge to ICAC findings. Credit:Brendan Esposito

The Baird government rushed a bill through state Parliament on Wednesday to validate the findings, which were jeopardised by a High Court ruling on the Independent Commission Against Corruption's powers.

Mr Duncan and his associates – John McGuigan, John Atkinson and Richard Poole – were already challenging the findings in court on grounds unrelated to the High Court decision.