"We do not want to see the two dewans as mere rubber stamps," he said, adding that the voices of members in both houses were always heard by the Government.
Speaking at a dinner to mark Tan Sri Abu Zahar Ujang's six-year tenure as the Dewan Negara (Senate) president, Najib said Abu Zahar, who started his stint on April 26, 2010, managed to make the Dewan Negara more "prominent and prestigious."
"A speaker (president) not only need to gain the trust of members who are representing the Government but also those in the Opposition so that it is seen as truly representing the people," he said.
"The difference in opinions is healthy in a democratic system," he added.
Abu Zahar's last day as Senate president is on April 25. A book on Abu Zahar was also launched during the dinner.
Those who attended were Defence Minister Datuk Seri Hishammuddin Tun Hussein, International Trade and Industry Minister Datuk Seri Mustapa Mohamed, Health Minister Datuk Seri S. Subramaniam, Wanita MCA chief Datuk Heng Seai Kie and MCA Youth chief Chong Sin Woon.