The number of government workers taking leaves of absence due to mental illness is on the rise, according to a government document released Friday.

The number of central government officials on sick leave for mental health problems rose to 1,160 in 2005 from 948 in 2004, according to the document issued in response to questions by Lower House lawmaker Miho Takai.

The document shows that the number of officials on mental health leave has risen 60 percent over the last four years. It did not specify how long the officials have been on leave.

The rise comes as workloads are increasing amid efforts to streamline government.

"Constant overtime is interfering with the workers' efforts to . . . put together policies and perform duties, and seriously affecting their mental and physical health as well as life," the paper said.

The government has been implementing a plan to trim the number of civil servants by more than 5.7 percent.