0312 GMT April 20, 2018
"We promise to boost our unity... and will proceed with selecting a single candidate," the main grouping, the Democratic Unity Roundtable (MUD) coalition, said in a statement, AFP wrote.
The coalition did not specify how it would choose its rival to Maduro. But on December 12, opposition lawmaker Luis Florido suggested consultations between the parties on holding primaries.
Venezuela's presidential election is scheduled to be held in late 2018.