Ota Sik, a survivor of Nazi concentration camps who became the architect of economic liberalization during Czechoslovakia’s ill-fated 1968 “Prague Spring,” but later was critical of “shock” liberalization in the 1990s, died Sunday at age 84. He died at a at a hospital in St. Gallen, Switzerland, where he taught economics after Soviet troops ousted the reformist Czech government in 1968.

Czechoslovakia’s communist government adopted Sik’s economic ideas in 1965 to kick-start stagnant industrial growth. His “new economic model” called for limited reforms of the Soviet system, including less central planning and a freer market economy – touted as a “third way” between communism and capitalism.

Sik, head of the economics institute at the Academy of Science, was appointed vice premier and economics minister in April 1968 as part of Premier Alexander Dubcek’s reform campaign to create “socialism with a human face.”

Warsaw Pact troops invaded on August 20, 1968, to crush the effort, but Sik was on vacation in Yugoslavia and escaped the crackdown. That October, he moved to Switzerland, where his family joined him several years later.

Born in Pilsen, Sik studied art in Prague and painted in his spare time as an office worker in the years before World War II. After Germany occupied western Czechoslovakia in 1939, he was active in the resistance before being arrested in 1940 and sent to the Mauthausen concentration camp in Austria. After the war, he studied politics and social sciences at Prague University.

When Czechoslovakia’s communist regime collapsed in 1989, new President Vaclav Havel appointed Sik to a board of advisers made up of prominent Czechs living abroad. But Sik retained his left-wing views and criticized the country’s shock economic liberalization, saying the immediate elimination of state subsidies would wreck many large enterprises.

“I cannot share a view which anticipates a quick rise in unemployment to hundreds of thousands or millions of people,” Sik told the then-East German daily Berliner Zeitung in 1990.

He estimated in 1989, with some accuracy, that it would take at least 12 to 14 years for Czechoslovakia’s economy to catch up with more prosperous Western nations. The two states born when Czechoslovakia split up in 1993 – the Czech Republic and Slovakia – finally joined the European Union in 2004.

Sik, who became a Swiss citizen in 1983, resumed painting following his arrival in Switzerland, exhibiting his pictures of colorful forms and shapes until late in life.