From SwissInfo:

Laws will be tightened from the start of January to clamp down on people conducting undeclared work - activity that costs the Swiss economy SFr 39 million ($35 million) a year.

Economics Minister Doris Leuthard announced the war on moonlighting with the backing of unions and employers. Measures include increased controls and sanctions coupled with less paperwork for low earners.

Workers and employers who fail to reveal earnings to the authorities costs the Swiss economy the equivalent of nine per cent of gross domestic product in lost taxes and social security contributions to the state and cantons.

The problem belongs to the same category as illegal prostitution and drug trafficking, supporters of new regulations say.