As many as 20,000 drug tests are carried out annually on employees and new staff recruits.
Those failing a drug test usually do so due to the use of cannabis, opiates, cocaine or amphetamine based substances such as ecstasy.
Testing levels in Finland are much lower than in Sweden and Norway.
Last autumn, legislation came into effect which allows screening for drugs only in those professions where safety or security factors are involved. These include transport and nuclear power security.