IRISH members of the Free Gaza movement have sought legal advice in the UK with a view to possible litigation against Israel following their arrest in international waters and subsequent confiscation of property.

The move comes as the Irish Palestine Solidarity Campaign (IPSC) dismissed as illegitimate last week's Israeli commission of inquiry into the shooting dead of nine activists on board a Turkish ship in May.

The inquiry ran into trouble when chairman Yaakov Turkel, a retired judge, threatened to resign his post unless its powers were extended beyond the original, limited mandate that barred soldiers from being subpoenaed.

These very limitations were criticised by the IPSC who said it could not recognise the authority of the commission and again called for in independent international body to take control.

IPSC spokesman Fintan Lane said: "We want an international inquiry; I was on a boat [in the flotilla] and it was a crime what happened. I have no faith in the Israeli inquiry whatsoever. It's clearly a very crude face-saving inquiry... On any level they killed nine people and now they are involved in a sort of semi-judicial cover-up."

For now, the IPSC and the wider Free Gaza movement is more focused on a string of legal actions designed to target the Israeli administration and extend publicity over the May "massacre of human rights activists".

The exact approach to litigation is unclear but property confiscated from flotilla members – including vessels – will be sought.

"I think it can be taken through some international jurisdictions; I don't know yet if the Israeli judicial system can be used, that is up to the lawyers."