He said the Al Saud rulers should await popular uprisings and social unrest in the oil-rich kingdom if the senior cleric is executed.
"The consequences of carrying out Sheikh Nimr's death sentence would be much more (serious) in the Saudi society than in the international community," Esmail Kowsari, member of the parliament's national security and foreign policy commission, told the Tasnim News Agency.
He said those who know the top cleric are certain about the truth of his statements and will definitely not remain silent if he is executed.
Earlier this month, unnamed European diplomatic sources said Saudi Arabia intends to carry out the death sentence of Sheikh Nimr.
Back in early March, a Saudi Arabian appeal court approved the death penalty of the prominent cleric.
Sheikh Nimr was detained in July 2012 following demonstrations that erupted in the country's Qatif region. He has been charged with disturbing the kingdom's security, delivering anti-government speeches, and defending political prisoners.
His arrest sparked widespread protests in the Arab country.