The NSW Liberal Party's casualty ward - otherwise known as the crossbench of the NSW Parliament - is filling up fast.

Bart Bassett's announcement on Wednesday brings to nine the number of MPs who have stood aside from the parliamentary party pending the outcome of Operation Spicer, the Independent Commission Against Corruption's investigation into illegal political donations.

Latest casualty: Londonderry MP Bart Bassett. Credit:Kylie Pitt

Two of those, Andrew Cornwell and Tim Owen, have also resigned from parliament.

Bassett's move brings ever closer the real prospect of the casualty list hitting double figures, given the inquiry has potentially a fortnight to run.