JAKARTA - The wife of Indonesia's former president Susilo Bambang Yudhoyono died at the National University Hospital (NUH) on Saturday (June 1).

Mrs Ani Yudhoyono, 66, had been treated for leukaemia at the hospital since February this year.

Democratic party spokesman Imelda Sari confirmed that Mrs Yudhoyono died at 11.50am. She was surrounded by her family at the intensive care unit.

"We hope for prayers from (the) Indonesian people. We hope that Ibu Ani's mistakes, both intentional and unintentionally, be forgiven," she told reporters in a MetroTV broadcast from Singapore.

Earlier this week, Mrs Yudhoyono, whose maiden name is Kristiani Herrawati, was treated in a special quarantine room at NUH after her health worsened to avoid viral and bacterial infection, which could potentially interfere with her recovery.

During her treatment at the hospital, she received many visitors and well-wishers, including Indonesian President Joko Widodo, who visited her in Singapore in February.

Mrs Yudhoyono condition was made known by her husband, who announced at a press conference in early February that his wife was suffering from blood cancer.

A week later, he said he would not participate in any campaign activities ahead of the Indonesian general election, adding that he would remain at his wife's side until her health improved.

Mrs Yudhoyono had been a pillar of strength by her husband's side during his presidency from 2004 to 2014. Prior to her treatment, she still accompanied him on his political tours to North Sumatra and Aceh.

She was widely known as an avid photographer and had been active on social media platforms, including Instagram, where she had 6.4 million followers. Despite her illness, she, for instance, shared her struggle with the blood cancer through her Instagram posts.

"We can judge a person's character, kindness, and sincerity from how she treats her daughters-in-law. Memo is one of a million," Madam Annisa Pohan, the wife of her first son Agus Harimurti Yudhoyono, wrote in her Instagram post about her mother-in-law, calling Mrs Yudhoyono by her affectionate name as given by her sons.

Singapore's Ministry of Foreign Affairs expressed its condolences on Mrs Yudhoyono's death.

"The Singapore Government extends its deepest condolences to Bapak Yudhoyono and family, and to the people of Indonesia, in this time of mourning," it said in a statement.

In Jakarta, President Joko Widodo expressed his deep condolences.

"I'm asking all Indonesian people to pray together for the dead so that she will be given the best place by the side of Allah and end her life well, and that her family will be given fortitude," he said in a Metro TV broadcast.

Mrs Yudhoyono's remains were transferred from the embassy on Saturday evening to Paya Lebar Air Base and flown to Indonesia's Halim Perdanakusuma airport in East Jakarta, and later transported to her house in Cikeas, Bogor in West Java.

She will be buried at the Kalibata Heroes Cemetery in Jakarta on Sunday.

Mrs Yudhoyono first met her future husband at the Indonesian Armed Forces Academy in Magelang, Central Java in 1973.

She was the eldest daughter of late Lieutenant General Sarwo Edhie Wibowo, who led the academy where Dr Yudhoyono studied at that time. The former led a purge of citizens affiliated to the Indonesian Communist Party which allowed strongman Suharto come to power, but then was marginalised by the New Order regime.

The couple got engaged in 1974 and married two years later. They have two sons, Agus Harimurti Yudhoyono and Edhie Baskoro Yudhoyono, who gave them four grandchildren.