Neda Topaloski entered with a press pass, stormed the room and shouted, "No to Bill 20" and "My uterus, my priority."
Topaloski is a well known-activist with the feminist group FEMEN, which has staged similar protests at several political venues in recent years.
Some critics of the government's Bill 20, legislation aimed at reforming the province's health-care system, say the changes will have an impact on access to health services, including abortions, in Quebec. Quebec Health Minister Gaétan Barrette says there is no plan to limit or impede access to abortion services.
The protester took off her top and stood beside stunned MNA Hélène David for more than 20 seconds before she was escorted out by a security officer.
Noemi Cimon-Mattar, a spokeswoman for Quebec's National Assembly, said that security is reviewing the incident, but had no further comment.
The temporary press pass was issued to Topaloski for Libération Next magazine.