This number included 140,000 people with jobs, or members of the so-called ‘working poor’, the data shows.
Single parents with small children, people living alone and people without further education were hardest hit.
In total 7.5 percent of Swiss people lived below the poverty threshold the year before last, up from 7 percent in 2015 and 6.7 percent in 2014.
The figure for Swiss citizens was 6.9 percent, while it was 9.3 percent for foreigners.
Poverty was defined by the FSO as an income of less than 2,247 francs a month for people living alone and 3,981 francs for a household comprising two adults and two children under 14.
A short-term phenomenon
The new FSO figures also provide, for the first time, a snapshot of the duration of poverty in Switzerland.
They show that one in eight people (12.3 percent) of people in Switzerland had an income below the poverty level for at least one of the four years from 2013 to 2106.
However, just 2.7 percent of people were poor in more than one of those four years, and just 0.9 percent of people were poor every year from 2013 to 2016.
This means most of this poverty was short-term, according to the FSO.
Call for action
The charity Caritas criticised the fact that poverty was on the increase despite strong economic growth.
Switzerland’s unemployment rate was a seasonally adjusted 2.9 percent in March. The State Secretariat for Economic Affairs in December revised up economic growth projections for 2018 to 2.3 percent.
Caritas also called for the federal government, cantons and communes to forge a national anti-poverty strategy.
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Meanwhile, the social welfare group Schweizer Tafel, which donates food to the needy, warned it was important poverty was not pushed to the edges of the national debate.
The group criticised politicians for their focus on “savings measures” at the expense of everything else.
Despite gloomy Swiss government projections that the country would see a budget deficit of 250 million francs in 2017, Switzerland managed once again to chalk up a surplus – of 2.8 billion francs.