The new policy, which came into effect Sunday, comes just days before the Syrian presidential election slated for Tuesday.
Zoubi said the decision was Lebanon`s business.
"It is an internal Lebanese affair that we will not interfere in," he said.
Zoubi said he believed the decision was aimed at preventing Syrians from voting in the June 3 presidential election.
Machnouk has denied rumors that the new policy - announced Saturday - was related to controversy over the enormous turnout of Syrian refugees and expatriates who voted at the Syrian Embassy in Yarze last week.
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