Jacqueline O'Brien, widow of the legendary trainer Vincent O'Brien, has died aged 89.

The daughter of a West Australian politician, Jacqueline O'Brien (nee Wittenoom) played a key role in her husband's record-breaking career.

She died early on Tuesday morning in a hospital in Dublin.

Her husband, who died in 2009 aged 92, was a colossus of the training scene, creating the Ballydoyle dynasty and dominating National Hunt racing before turning his attentions to the Flat.

Married in 1951, the O'Briens had two sons, David, trainer of Derby winner Secreto, and Charles, and three daughters, Elizabeth, Susan and Jane.

Susan is married to John Magnier, the head of the Coolmore stud operation.

"It's very poignant on the opening day of Cheltenham, a place that Jacqueline and Vincent were so closely associated with for many years," Horse Racing Ireland chief executive Brian Kavanagh said.

"She was a wonderful lady, an institution in Irish racing for decades.

"She was much more than just the wife of Vincent O'Brien. In her own right she was a fantastic lady - a very talented photographer, very talented fund raiser, philanthropist and a key member of the Ballydoyle team through the golden years."

The Vincent O'Brien County Handicap Hurdle is run on Friday, the last day of the festival at Chelthenham, where Charles O'Brien is scheduled to run Henry Higgins.