Abdo Hussameldin, the deputy Minister of Oil and Mineral Resources announced his decision to resign from the government and from the Arab Baath Party.
Hussameldin became the most high-ranking official to abandon President Bashar Assad since the anti-regime protests began last March.
The move was lauded by Syrian opposition members who expressed hope that additional government officials and civilians would follow.
"I am joining the revolution of this Nation, which did not and will not accept injustice despite the brutality of this regime and its supporters to crush the people who are seeking their dignity and freedom. I salute the Free Syria Army which refused to be with the butcher against the victim. And I call on them to be united to end this unjust regime."
Burhan Ghaloun, head of the Syrian National Council said he hailed the deputy oil minister for his decision, the British daily The Telegraph said.
"I expect for sure that there are other government officials and politicians who will follow suit," Ghaloun currently in Cairo was quoted saying. Ghaloun urged "the Syrian opposition to come together to work with us to find a solution that will respect the aspirations of the Syrian people," the newspaper quoted him saying.