The woman accused of murdering her baby son, who was found in the waters off Bedok Jetty last November, has been found fit to have her plea taken, but was of unsound mind at the time of the alleged offence.

The prosecution told the court this when Lim Ann Nee's case came up for mention on Tuesday.

The 44-year-old woman has been charged with causing the death of her 17-month-old son in the sea off East Coast Park on Nov 25 last year. Emilien Lacroix's body was found floating about 300m from Bedok Jetty three hours later, after being spotted by a passenger on a passing boat.

Lim had been remanded at Changi Women's Prison for psychiatric evaluation.

The prosecution successfully applied for her to be remanded at Central Police Division for investigation. She will be back in court on Jan 21.