A clear majority was expected for the regulation, which was due to come into force at the beginning of February.
Austria’s right-wing Freedom Party, FPÖ, on the other hand, has fiercely criticized the plan.
Compulsory vaccination would apply to all citizens over 18 years of age.
Exceptions were planned for pregnant women and all those who were not allowed to be vaccinated for medical reasons.
The Bundesrat, the upper house of the Austrian parliament that represents the federal states, was expected to approve the law on February 3.
The new law was the subject of a controversial public debate.
Tens of thousands regularly demonstrate against government-imposed coronavirus measures and the prospect of compulsory vaccination.
Mandatory vaccination was supposed to significantly reduce the impact of future waves of coronavirus and prevent lockdowns, for example.
Currently, about 75 percent of vaccinated people in Austria have at least a complete basic immunization.
The objective for the effective protection of the population was 90% of those who can be vaccinated.