Irish rower Sanita Puspure has withdrawn from the single sculls B final at the Olympic Games, revealing that she has been unwell for several days.

Puspure turned in a surprisingly disappointing performance in her semi-final, finishing fifth in a race in which she was expected to challenge.

Eyebrows were raised given the World Champion's lack of competitiveness in that semi-final and in a statement from the Olympic Federation of Ireland, Puspure confirmed that her preparations for that race were hampered by illness.

"Over the past few days, I have not been well, and I had to make the difficult decision to withdraw from the Olympic regatta," the statement read.

"This is really disappointing as I had been going well over the past few months and had hopes to continue this good form.

"The Olympics is always a big goal so it's heart-breaking to have to pull out in this manner."

Puspure had been considered a genuine medal contender in the single sculls, but was never at the pace needed to progress from the semi-final and finished a distant fifth in that race.