The FBI is having trouble filling jobs for its cybersecurity programs because of comparatively low pay and rigorous background checks, an auditor's report says.

The Justice Department's office of the inspector general released Thursday said the FBI has not hired 52 of the 134 computer scientists for which it was authorized, and that five of its 56 field offices did not have a computer scientist for its Cyber Task Force.

The report said the FBI needs to focus on "recruiting and retaining highly-skilled, technically trained cyber professionals" and to expand cooperation with the private sector to fight cyber threats.

"Recruitment and retention of qualified candidates remain a challenge for the FBI, as private sector entities are often able to offer higher salaries and typically have a less extensive background investigation process," the report said.

"We believe that the FBI should continue its creative recruitment and retention efforts, including targeted use of the (student loan repayment program) and increase the mobility of former employees with critical skills, to attract and retain highly skilled cyber professionals."

The inspector general's report said the FBI has tried to fill the gaps by working with private contractors, and has also stepped up recruitment and training programs at colleges and universities.

The report said that while recruiting is difficult, "most of the FBI cyber agents we interviewed told us that it is the FBI's mission that motivates them to stay at the FBI rather than leave for more lucrative positions."

The report appears to confirm anecdotal evidence about difficult relations between the US security establishment and technology industry, which have worsened since the 2013 revelations about vast US government surveillance programs.

The report noted the FBI is also hampered in its efforts to boost cybersecurity efforts by a lack of cooperation from the private sector.

"The private sector reluctance to share information has been further affected by the distrust of government following the Edward Snowden leaks" about US surveillance programs, the report said.

"Several private sector representatives told us that providing information to the FBI is akin to sending it into a black hole -- the information goes in and the entities never hear any more about it."

The report said the FBI should "strengthen its outreach efforts to improve sharing and collaboration with private sector entities" where feasible.