The retired general failed to appear before a special court in Islamabad after some explosives and two pistols were found in a bag on the road between his home and the court, Geo News reported.
The report said the prosecutor had asked the court to issue a non-bailable arrest warrant against Musharraf when he did not appear for his trial before a three-member panel headed by Justice Faisal Arab.
However, an attorney for Musharraf told the court about the threat to his client's life. Earlier, the court had delayed the start of the trial after being informed by police about the discovery of the explosives.
The court adjourned the hearing until Jan. 1. Geo News said a bomb disposal squad later reached the site and defused the explosive.
The trial for Musharraf was ordered after the Islamabad high court on the previous day dismissed petitions objecting to being tried by a special court instead of a military court.
The treason charge stems from Musharraf's suspension of the constitution and imposition of emergency rule in Pakistan in 2007.
Musharraf, 70, who has said the charge is politically motivated, held power from 1999 until 2008 following a coup that ousted Prime Minister Nawaz Sharif. Sharif has returned as prime minister for a third time after winning elections last May.
Pakistan has been under various military rulers for nearly half of its history since becoming independent in 1947. Musharraf's trial, however, will be the first when a former military ruler will be tried for treason.
Musharraf returned to Pakistan in March after being in self-imposed exile.