The Department of Foreign Affairs received hundreds of calls yesterday from concerned friends and relatives of Irish citizens working or living in London.
A spokeswoman said last night it had no reports of Irish people being killed or seriously injured in the attacks.
Fifteen dedicated phone lines were set up after news of the blasts came through. An emergency centre was also established in the Irish Embassy in London to deal with inquiries from Irish citizens based in Britain. The department's emergency phone number is 1800 242 548.
The Irish Embassy in London can be contacted at 0207 201 2508 or 0207 201 2501.
The department asked people seeking news of friends or relatives in London to contact their emergency number rather than the embassy.
Airlines flying to and from London said normal schedules would operate today. Ryanair and EasyJet said they would facilitate customers who do not wish to travel by waiving the normal change-of-booking fees.
Garda authorities have established a special incident desk to act as a liaison with UK authorities on the attack and any subsequent investigation.