Legal action against former Sunday Independent columnist Eoghan Harris and Twitter is to be heard in Dublin's High Court next month.
Prominent journalists Allison Morris and Aoife Moore are taking action in a bid to discover who was behind social media accounts which trolled them,
An emergency hearing has been listed for June 4.
Both journalists are represented by Belfast firm Phoenix Law.
Ms Morris, an award-winning former Irish News journalist now working for the Belfast Telegraph, said she suffered "sustained and obsessive attacks" via anonymous accounts.
Ms Moore, a Derry-born political correspondent for The Irish Examiner, said she was abused in more than 120 tweets from two separate accounts in just 12 months.
Mr Harris's contract with the Sunday newspaper was terminated earlier this month after it emerged he was involved in an anonymous Twitter account which targeted several high-profile figures in Irish public life, including journalists and campaigners.
A fierce critic of Sinn Féin, Mr Harris said he was among six people involved in the Barbara J Pym account.
The account has been suspended by Twitter along with several others linked to it.
Several other people, including Belfast film-maker Seán Murray and journalist and author Paul Larkin, have already announced they are taking legal action following the revelations.
