Jakarta – A former top Indonesian spy pleaded not guilty Tuesday to ordering the murder by poisoning of a celebrated human rights activist who had exposed military abuses.

Muchdi Purwopranjono, 59, an ex-deputy chief of the State Intelligence Agency (BIN), is on trial accused of plotting activist Munir's murder by arsenic poisoning as he flew from Jakarta to Amsterdam in 2004. "We reject all the charges," defence lawyer Muhammad Lutfi told the court.

Prosecutors have said the killing was an act of revenge after Munir had uncovered the kidnappings of 13 activists allegedly by special forces under Muchdi's command in the late 1990s. The scandal led to the former general's sacking as special forces chief, according to the indictment.

His trial is the first time a high-ranking figure in the military establishment has faced justice over the murder, which rights activists have long suspected was the work of the secret intelligence services.

Munir, who died aged 38, was the leader of independent rights watchdog Kontras and a vocal campaigner for victims of military abuses under the 1966-1998 Suharto dictatorship.

Defence lawyers said there were several holes in the state's case against Muchdi, who showed no emotion as he listened to the proceedings.

"The prosecutors said that the killing took place in Changi airport in Singapore but in other parts of the indictment it was mentionned that it took place on the plane transporting the activist," Lutfi said.

He said the international community had pressured President Susilo Bambang Yudhoyono to prosecute someone other than Pollycarpus Priyanto, a pilot with national carrier Garuda who was sentenced to 20 years' jail over the murder.

"There was a letter signed by 50 members of the US Congress and from the EU parliament... They asked why it was only Pollycarpus that was brought before the court," he told South Jakarta district court.

Prosecutors allege Muchdi ordered Priyanto to poison Munir with arsenic during a Garuda flight from Jakarta to Amsterdam via Singapore.

Muchdi has been in custody since he turned himself in to police on June 19 in Jakarta. The trial will resume on Thursday.