The High Court ordered a two-week jail term for businesswoman Jannie Chan to take effect, after she continued to disobey a court order that restrained her from defaming and harassing her former husband.

Chan, 72, who co-founded luxury watch retailer The Hour Glass with former husband Henry Tay, 73, was given the jail term for contempt of court on Aug 2 last year.

The judge, however, had given her a last chance to avoid prison by suspending the sentence for a year, provided that she stopped defaming and harassing Dr Tay, underwent monthly psychiatric treatment and kept her former husband updated about each session.

Merely a day later, Chan flouted the conditions. Over two days, she posted allegedly defamatory comments on Facebook.

Chan also sent hundreds of allegedly defamatory and harassing e-mails to various recipients.

She even turned up at Dr Tay's new home, took photos of it and forwarded them to others, said his lawyer, Ms Megan Chia.

Chan also failed to show proof of three psychiatric appointments.

Ms Chia said even though Dr Tay took steps to re-route her e-mails to his junk folder, he continues to suffer defamation and harassment.

On Monday, the court granted Dr Tay's application to lift the suspended sentence. "Her conduct has been unremorseful and unrepentant. In fact, she has been intentionally sending the harassing and defamatory e-mails to new recipients," noted Justice Hoo Sheau Peng. The judge rejected Chan's contention that the e-mails were meant to elicit a response from Dr Tay and others about the plight of her daughter, Audrey. The court heard that Audrey was facing criminal charges and diagnosed to have a psychiatric condition.

Justice Hoo said she failed to see how Chan's "wilful and irresponsible behaviour" of sending e-mails to other people helped the situation.

Chan was granted a stay on the sentence after her lawyer, Mr Eugene Thuraisingam, said she was appealing it.

Chan and Dr Tay ended their 41-year marriage in 2010. He sued her in 2014 for sending e-mails which he said were defamatory or amounted to harassment. The recipients included friends, employees and Cabinet ministers.

The lawsuit was settled and Chan was ordered to stop. However, she persisted in flouting the order.

This is the third time Dr Tay has pursued contempt of court proceedings against her. He dropped the case the first time after she apologised, and she was fined $30,000 the second time.