The problems also hampered communications for the city's fire department.
Oakland Mayor Jean Quan said the city has been working hard to fix its aging radio communications system but there won't be a long-term solution until a new system in fully implemented later this year.
The new system is being tested, and city officials hope it will be completely in place by the end of the summer, she said.
The new system complies with national standards for digital radio communications, which are called Project 25, or P-25, Quan said.
Reygan Harmon, Quan's senior policy advisor for public safety, said the police radio system was affected from about 8 a.m. to 10 a.m. today.
Harmon said there also were "challenges" with the backup system that was used while the communications system was down so the Police Department had to use another backup system.
Harmon said that until the new system is in place, Oakland's Information Technology Department is working with the Police Department to try to resolve any problems as quickly as possible.
She said the Police Department is working to ensure that priority calls are addressed even when there are problems with the radio system.