Breedagh Hughes, Northern Ireland secretary from the Royal College of Midwives, said it was her understanding that the timescale for closure of the unit in Lisburn was between one year and 18 months raising concerns that more pressure will be put on already overstretched maternity services in Belfast and Craigavon.

It is understood the chief executive of the South Eastern Health Trust was to make an announcement today over the future unit.

The South Eastern Health Trust has already confirmed to the Belfast Telegraph that it had been reviewing services, including obstetrics, at all of its hospitals. But would not confirm the maternity unit at Lagan Valley was set to close in 18 months.

Around 1,100 babies are delivered at Lagan Valley each year. Its closure has raised concerns that more pressure will be put on already overstretched services in Belfast and Craigavon, because many local women will have nowhere else to go.

Ms Hughes said the organisation had been campaigning to have a Community Midwifery Unit put in place instead.

However, no assurances have been given, raising concerns that women in Lisburn will be left with no maternity services.

"It's our view that if the obstetrics unit is to close on safety grounds, it should immediately be replaced with a community midwifery unit," Ms Hughes said. "The maternity units at the Royal Victoria Hospital and Craigavon are bursting at the seams. Around 1,100 babies are born at Lagan Valley each year. Where are these women going to go? Neither the Royal Jubilee (RVH) or Craigavon have the capacity for them. Our view is if the obstetrics unit is unsustainable then they need to get a Community Midwifery unit immediately so some women are able to stay there and reduce the work load on the other two hospitals because while some (women) might choose to go to the Ulster or Antrim, most will go down the M1 to the Royal or Craigavon."

A South Eastern Trust spokeswoman said no decision had been made on the future of the maternity unit confirming only that it, and other services in the Trust's area, were under review and an announcement was due to take place later today.

Royal College of Nursing Northern Ireland director Mary Hinds said the organisation was also aware of plans to "staff-side" organisations as part of the Comprehensive Spending Review but that members have, as yet, had not approached them with concerns about these proposals.