Published Tuesday, 07 February 2012
Dr Paisley is receiving treatment at the intensive care unit of the Ulster Hospital in Dundonald after suffering heart problems last weekend.
In a statement on Monday, the 85-year-old's wife, Baroness Paisley, requested "the family's privacy be respected at this difficult time".
On Tuesday morning, UTV's Political Editor Ken Reid said: "Ian Paisley's family has been at his bedside all night, Ian Paisley Junior arrived at the hospital at 6.15am".
Ian Paisley Jnr confirmed the family were there but did not give any further details on Ian Paisley Snr's condition.
UTV's Political Editor Ken Reid
"It seems that he has a serious heart condition, but the only statement has been from Eileen Paisley who asked for privacy and said it is a very difficult time for the family."
Ian Paisley became Northern Ireland's First Minister when he was elected into power alongside Sinn Féin's Martin McGuinness in 2007.
A statement from the Office of First and deputy First Minister revealed Peter Robinson and Mr McGuinness have both been in contact with the Paisley family.
The First Minister and the deputy First Minister have offered their best wishes to Dr Paisley and his family and call on the community to give prayerful support to Ian and his family at this time.
OFMDFM statement
Mr Paisley stepped down from political life in 2010. Last December, he preached his final sermon after standing down as moderator of the Free Presbyterian Church.
In an interview with UTV at the time, he said of his ministry: "I would say the average of a man that has good health should do about 25-30 years, but I have doubled that so I have done very well!"
Asked whether he felt his mantle as a politician or a churchman has been the most important, Rev Paisley said he wished to be remembered as a "gospel man".
He said: "Oh by long and far the gospel man. Really the fact that I was in politics came as a result of the faith that I preached."
After retiring from both church and political life, he said he planned to write his autobiography.