A woman who survived a farming accident which killed a young rugby star, his father and brother has been released from hospital.

Emma Spence, the sister of Ulster Rugby's Nevin Spence, was being treated in Belfast's Royal Victoria Hospital for the effects of inhaling fumes following the weekend slurry tank tragedy.

Her two brothers and father were overcome by gas after falling into the tank at their farm on the Drumlough Road in Hillsborough, Co Down, at around 6pm on Saturday night. The talented 22-year-old rugby player died along with his 30-year-old brother, Graham, who was married with two children, and their 52-year-old father, Noel.

Ms Spence, a well-known artist, was discharged from hospital on Sunday night as relatives revealed that the three men died trying to save each other.

Fans and friends of Nevin Spence signed a book of condolence and left tributes at the ever-growing wall of flowers and shirts at one end of Ulster Rugby's Ravenhill ground in Belfast, while the team's RaboDirect PRO12 game on Friday in Italy against Zebre looks set to be postponed. Ulster Rugby chief executive Shane Logan said: "It will almost certainly be postponed."

There is widespread shock at the devastating blow to the remaining family members, Essie Spence and her daughter, Laura. The grieving relatives said: "The families of Noel, Graham and Nevin Spence are trying very hard to come to terms with their tragic loss. The three men were very close to each other in life, and that love was expressed in their final moments trying to help one another. The family is being supported and comforted by other family members, friends and neighbours. Arrangements for a thanksgiving service for the three are currently under way and details will appear in the press in due course."

The statement was released by Rev Rodney Stout, senior pastor at Ballynahinch Baptist Church, who said the family asked the media to respect their privacy at this difficult time.

The Health and Safety Executive for Northern Ireland is investigating the circumstances to establish a clear picture of how the tragedy unfolded.

Irish Tanaiste Eamon Gilmore visited Ravenhill to pay his respects on behalf of the Dublin Government. Mr Gilmore described the accident as a "deep, deep tragedy". Northern Ireland's Deputy First Minister, Martin McGuinness, later met officials at Ravenhill and penned his own tribute in one of the books of condolence. He said the Stormont Assembly had been rendered a "solemn and quiet" place as a result of the tragedy.

Former Stormont first minister Ian Paisley also visited Ravenhill to sign one of the books. The long-time Free Presbyterian moderator said he knew the Spence family and invoked biblical references to express confidence that their strong Christian faith would sustain them. "It touched me, it really shook me," he said of the tragedy.