HELSINKI (AFP) -- Finland's parliament passed a controversial law obliging the country's doctors to inform police if a patient is in such poor health that he poses a threat to himself or others when at the wheel of a car, officials said.

"The doctors should make a report to the police if their patients, or people that are in long-term care or are chronically ill, should not drive anymore," Terhi Hermanson, senior medical officer at the health ministry, told AFP.

Under the law, doctors will have to inform the police even against the will of their patients, she noted.

The law is set to take effect in September, but is controversial, and was adopted against the advice of Finland's doctors' union.

"We think it is a bad idea that the doctors are made informants for the police," Markku Aeaerimaa, the managing director of the union, told Finnish news agency FNB.

Opticians will also be required to inform authorities if any of their clients above the age of 45 have such poor eyesight that their driving would pose a danger to themselves or their environment, the ministry said.