The allegation surfaced at a time when the revitalized opposition under Anwar was making moves to engineer parliamentary defections aimed at bringing down Prime Minister Abdullah Badawi's government.
Anwar planned to lead hundreds of his supporters to a suburban Kuala Lumpur police station to file a report saying the current police chief and attorney general fabricated evidence against him in the 1998 sodomy case when they were part of a team that investigated and prosecuted him.
Anwar said in a statement on Sunday that the new sodomy case was "organized by interested parties" to smear him because he had recently obtained evidence implicating Inspector General of Police Musa Hassan and Attorney General Gani Patail in fabricating evidence in his 1998 sodomy conviction.
Anwar, who took refuge in the Turkish embassy for 36 hours until Monday evening, said the new allegations were a political conspiracy to thwart his return to parliament.
Anwar said on Monday he had planned to announce this week he would run in a parliamentary by-election. Winning a seat would be the first step on the road to his ambition of leading the opposition to power for the first time in Malaysian history.
The loose opposition alliance made historic gains in the March 8 general election, winning five of 13 state governments and coming within 30 seats of taking control of the 222-member parliament.
Anwar has also filed a defamation suit against his accuser. Anwar's political party says the aide, Saiful Bukhari Azlan, was planted in their camp by people close to the ruling National Front.
Neither the national police chief nor the attorney general have commented on the case. But other officials, including the prime minister and deputy prime minister, have strongly denied the government had anything at all to do with it.
Saiful, who was taken to hospital for examination, has been released and is now under police protection, according to media reports quoting his family.
But the Star newspaper on Tuesday quoted his uncle as saying government officials would not help when approached about his story and some police stations turned them away as well when they tried to lodge a police report.
Federal criminal investigations chief Bakri Zinin has vowed to protect the accuser and accused and to conduct a fair and thorough investigation."
The United States cautioned against any politically motivated investigation into Anwar.
"The main point for us is that the rule of law needs to stand above politics," said Tom Casey, the U.S. State Department spokesman. "And we would certainly oppose any use of law enforcement or judicial procedures for anything other than legitimate purposes of the law."
Casey noted Anwar had been convicted previously on similar charges. "So we would hope that there's not a pattern here."
"But certainly we would be concerned that anything that is done, be done in a way that is appropriate, that is a legitimate investigation of charges that might exist under Malaysian law and would not be anything that was a politically motivated investigation or prosecution," Casey said.