Mr Gilmore described the woman’s 30 years of captivity as “astonishing”, adding Irish embassy officials have made contact with the Metropolitan Police.
The 57-year-old Irish national was among three women who were freed after claims that they were held as slaves in an London house.
Two people arrested by police in connection with the incident have been released on bail.
Speaking at a John F Kennedy memorial in Dublin, Mr Gilmore said his officials are on standby to provide consular assistance.
“The embassy has been in touch with the Metropolitan Police. We have told them that we’re available to provide any consular assistance that is requested – to be of any assistance that we can be,” according to the Labour Party leader.
“I’m very shocked by it. Thirty years is an astonishing long time for somebody to be locked up in a state of slavery. But I think we have to see more details emerging about what happened here. I think probably the immediate need is going to be for medical assistance and support for the three women who were so shockingly incarcerated in this way.”