Both chambers have voted to increase jail sentences to a maximum of five years for people found guilty of coercing others into a marriage. The law is to apply regardless of whether the marriage was agreed outside Switzerland.
The Senate followed the House of Representatives tightening the law, notably banning marriages to minors. The minimum age for marriage in Switzerland is 18.
Senator Christine Egerszegi, spokeswoman for the committee on political institutions, said there was broad agreement in parliament that measures to combat such marriages were urgent.
“It is a crime and always goes against human dignity,” added Justice Minister Simonetta Sommaruga.
She said the aim of the bill was to ensure that forced marriages can be cancelled more easily and that the onus is not placed on the victims of forced marriages.
There was no mention in Tuesday’s debate of the number of cases - notably in the immigrant community - in Switzerland each year, but the bill specifically targets practices abroad.
Under the new law, Swiss registrars must refuse to officiate when they come across forced marriages and report suspected incidents to the justice authorities.
But further discussions are needed in parliament to iron out differences. The Senate wants to invalidate every forced marriage, while the House last December came out in favour of allowing exceptions if both parties of a forced marriage agree to continue the union voluntarily.
Pascale Bruderer, senator for the Social Democrats, expressed doubts as to whether the task of the judges will be made easier by the legal amendment and whether the victims of forced marriages can be given enough protection.
Current Swiss legislation foresees a maximum jail sentence of up to three years in cases of coercion where pressure or threats were used to force two people into a marriage.
The Surgir Foundation in 2006 estimated that there are about 17,000 people in Switzerland who are victims of forced marriages. The Lausanne-based non-governmental group credits itself with breaking a taboo by launching a public campaign on the issue.
In 2010, authorities in the city of Zurich commissioned a report on forced marriages. It found that up to 40 cases of advice on the issue are sought every year in Switzerland’s largest city. Other studies have put the figure higher.
Those forced into marriage tend to come from eastern Europe, the Middle East, Central Asia, North- and sub-Saharan Africa, according to experts.
The Surgir Foundation defines victims of forced marriage as individuals who are married against their will through physical or psychological pressure, or those who run away in order to avoid a forced marriage.
There are no exact figures available but experts say forced marriages are more frequent in societies in eastern Europe, the Middle East, central Asia as well as North- and sub-Saharan Africa.
So-called arranged marriages, if fully accepted by both parties, do not violate human rights according to Surgir.
By Urs Geiser, swissinfo.ch and agencies