A judge has said he is determined the Omagh bomb compensation case will go ahead in April despite complications.
Twenty-nine people were killed in the Omagh bomb
One of the men being sued by the families, Colm Murphy, is involved in legal proceedings in the Republic over offences connected to the atrocity.
But Mr Justice Morgan said this should not interfere with the case.
It involves alleged Real IRA leaders, Michael McKevitt, Seamus Daly, Liam Campbell, Colm Murphy and Seamus McKenna, who all deny liability.
Lord Brennan, senior counsel for the families, taking the £14m civil action, said in the High Court in Belfast on Thursday that his team was currently seeking material from police on both sides of the border.
"The PSNI's view is that they will co-operate to the extent they feel able to," he added.
The compensation trial is expected to get underway on 7April, and to last up to two months.