"Why are we having the hearing today since I have only one Cambodian lawyer," Nuon Chea asked the panel of judges, adding that the situation was "not consistent with international standards".
"If the hearing goes ahead, I don't believe it will be fair to me," he said.
Born in 1923, Nuon Chea is the most senior surviving Khmer Rouge leader
Served as deputy to Khmer Rouge leader, Pol Pot, and was group's top ideologue for more than 30 years
Played a key role in carrying out Khmer Rouge plan to relocate millions of Cambodians to vast collective farms, which later became the notorious "killing fields"
Arrested in September 2007, at his home in Pailin near the Thai border
Facing charges of war crimes and crimes against humanity
A key member of Nuon Chea's defence, Dutch attorney Victor Koppe, has yet to be admitted to Cambodia's Bar Association, a requirement for foreign lawyers wishing to represent tribunal defendants.
No new date has been set for his appeal, raising fears of yet further delays to the tribunal process more than a quarter of a century after the Khmer Rouge were forced from power.
"It's regrettable that it's been postponed," co-prosecutor Robert Petit told AFP.
"Any delay in this court is regrettable. Any delay in getting at the truth in this matter and justice for the victims is regrettable," he added.
The former deputy to Khmer Rouge leader Pol Pot - who died in 1998 – Nuon Chea was arrested last September and faces charges of war crimes and crimes against humanity.
He is one of five former Khmer Rouge leaders awaiting trial, expected to start later this year.
|Some 1.7 million people were killed during|
the Khmer Rouge's 1975-79 rule [AFP]
Nuon Chea is the second Khmer Rouge senior official to appeal his detention, following a similar move by Kang Kek Iew, also known as Duch, who headed the group's notorious Tuol Sleng prison and interrogation centre.
Duch's appeal was rejected by the court, which said he could attempt to flee the country or interfere with witnesses if he was freed.
Speaking before Monday's court appearance, Son Arun, Nuon Chea's lawyer, said his client "feels an absence of freedom in his detention, where all he does is eat and sleep".
However, the panel of Cambodian and international investigating judges has said it sees Nuon Chea's continued detention as necessary to prevent him from pressuring witnesses or destroying evidence, as well as for his own safety.
The former Khmer Rouge second-in-command is accused of playing a key role in the deaths of some 1.7 million people during the group's 1975-79 rule.
During that period, the Khmer Rouge emptied Cambodia's cities, exiling millions to rural areas in a bid to forge an agrarian utopia, outlawing schools, religion and currency.
The tribunal, convened in 2006, has charged Nuon Chea with "murder, torture, imprisonment, persecution, extermination, deportation, forcible transfer, enslavement and other inhumane acts".
The tribunal is expected to hear documentary evidence that Nuon Chea personally ordered the murder of 14,000 people held at the Tuol Sleng prison, a former Phnom Penh high school.
Nuon Chea surrendered to the Cambodian government in 1998 after the final remnants of the Khmer Rouge collapsed in 1998 and he was given a formal pardon.
In an apology of sorts after the surrender he told reporters: "Naturally, we are sorry, not only for the lives of the people, but also for the animals. They all died because we wanted to win the war."