BUCHAREST (Reuters) - Romanian Prime Minister Victor Ponta said on Tuesday he would respect and implement a ruling by the Contitutional Court that struck down a referendum to oust his rival, President Traian Basescu.

"I want to send a signal of stability to Romanians: The court decision will be respected and implemented," Ponta told a news conference.

The court ruled earlier on Tuesday that a July 29 government-sponsored referendum to remove Basescu was invalid because turnout failed to meet the required 50 percent threshold, despite the government's argument that an update to voter lists may lower the quorum.

(Reporting by Radu Marinas; Writing by Jan Lopatka; Editing by Jon Hemming)