Ieng Thirith, 76, facing trial for crimes against humanity, told the court that defence lawyers would speak on her behalf during her appeal against detention, saying, "I am too weak."
As the regime's former social affairs minister, she is one of five top cadres in the sights of the UN war crimes tribunal over atrocities committed during the communist Khmer Rouge's 1975-1979 rule.
The health of the ageing suspects is an ongoing concern. Ieng Thirith's husband, former Khmer Rouge foreign minister Ieng Sary, was hospitalised Monday evening for blood in his urine, court spokesman Reach Sambath said.
It was the ninth time Ieng Sary, 83, has been rushed to hospital since the pair were detained by the court in November 2007, the spokesman said.
In documents read to the court Tuesday, investigating judges argued it was necessary to keep Ieng Thirith in jail to protect her security, preserve public order and ensure she did not flee from trial.