The wife of Singapore Minister Mentor Lee Kuan Yew is in serious condition after suffering a brain haemorrhage.

She suffered sudden weakness on her left side and slurring of speech around noon on Monday, according to a statement from the Minister Mentor's Office.

Mrs Lee, 87, was taken to the National Neuroscience Institute for an urgent brain scan, which revealed massive right intracerebral haemorrhage.

She was subsequently admitted to the Neurointensive Care Unit at Tan Tock Seng Hospital. The haemorrhage stabilised after close monitoring and treatment, and she was transferred to the general ward on Wednesday.

Mrs Lee is currently in serious condition although she is able to recognise immediate family members, say latest reports.