SINGAPORE - The Family Court is expected to decide on Monday whether a rich widow has the mental capacity to change her mind over who should look after her welfare and $40 million worth of assets.

The closed-door hearing on 87-year-old Madam Chung Khin Chun's bid to cancel the Lasting Power of Attorney (LPA) she granted to former China tour guide Yang Yin in 2012 was adjourned on Friday.

The court called its second expert witness Professor Chiam Peak Chiang, a senior consultant at the Institute of Mental Heath (IMH) to give her testimony. She was appointed by the court in October to examine Madam Chung and her report was submitted earlier this month.

Her nearly two-hour testimony came after another psychiatrist Calvin Fones was called to testify on Thursday on his examination of Madam Chung in September.

Dr Fones, who is in private practice, had previously certified that the widow had the mental capacity to cancel the LPA. On the basis of his report, Madam Chung applied to the Office of Public Guardian (OPG) in September for the LPA to be cancelled.

The OPG then applied to court to have an independent medical expert from the IMH examine Madam Chung, while suspending Yang's powers under the LPA.

The OPG said the move was "necessary to safeguard and protect the interests and assets of Madam Chung". It added that it will make a decision on the cancellation of the LPA after the court makes a ruling on her mental capacity.

Madam Chung, who was diagnosed with dementia this year, met the 40-year-old Yang in Beijing in 2008. Her niece Hedy Mok, 60, has accused him of manipulating the widow to seize control of her $40 million worth of assets, which included a $30 million bungalow. He is under police remand after being charged with faking 331 of his firm's receipts.

Yang is also being probed by the Ministry of Manpower and Immigration and Checkpoints Authority on how he obtained his Employment Pass in 2009 and permanent residency in 2011.