NBI employees said it was time to return the agencys helm to an "insider" after the sudden death of former director Reynaldo Wycoco last month.
The NBI is the countrys premiere investigating body and it does not need former generals with "dubious reputations" to lead it, they added.
The NBI employees said they would prefer someone who rose from the ranks like Mantaring, who has earned the respect of the NBI during his 35 years of service.
"The NBI needs the consistency of a Mantaring to continue its mission of protecting this countrys public," they said.
"We appeal to President Arroyo to reward Mantarings record of achievement as assurance to the NBI rank and file that those that work hard and do well can rise through the ranks and eventually become NBI director," the bureau personnel said.
They said Mantaring has remained true to the bureau during his 35 years of service, and that he was named assistant director, the second highest post in the bureau.
"In the last two years, (Wycocos) most trusted assistant has been Assistant Director Mantaring," they noted.
"While Wycoco was busy parrying the shots from media and other external factors, (Mantaring) kept the whole NBI machinery grinding forward, doing its job.
"While Wycoco attended to the requirements of Congress, the Senate and Malacañang, Mantaring made sure the NBI continued with its day-to-day functions of investigation and crime solving," the resolution added.
Three NBI employees organizations have submitted a copy of their resolution to Mrs. Arroyo, openly expressing their support to the 58-year-old Mantaring to become the bureaus 17th director.
These are the NBI Investigators Mutual Benefit Association Inc. (NBIIMBAI), the NBI Employees Association (NBIEA), and the NBI-Retired and Ex-Employees Association Inc. (REXAI).
Among those reportedly interested in the NBIs top slot are Philippine National Police chief Director General Arturo Lumibao, retired PNP chief Edgar Aglipay, retired Chief Superintendent Reynaldo Berroya, Manila police director Chief Superintendent Pedro Bulaong, and retired general Ernesto de Leon.
Other contenders are Supreme Court assistant court administrator Reuben de la Cruz, a former Marikina regional trial court judge; and Judges Oscar Barrientos of Manila RTC, Leoncio Janolo Jr. of Pasig RTC, and Ralph Lee of Quezon City RTC. Dela Cruz, Barrientos and Lee are former NBI agents.
Mantaring began as a clerk at the NBI in 1968 and took up law at night until he obtained his law degree in 1972.
He passed the bar exams in 1973.
After serving as line agent and chief of operation divisions, he was named deputy director for comptroller services in 2001.
The following year, he was appointed deputy director for administrative services, and in 2003 he was named deputy director for special investigation.
In 2004, he was promoted to NBI Assistant Director.
When Wycoco lapsed into a coma on Nov. 23 following a sudden stroke, the President named Mantaring officer-in-charge of the NBI.