Venezuelan opposition leader Juan Guaido's faltering efforts to oust President Nicolas Maduro are facing a new challenge in the form of an influence-peddling scandal that has left disillusioned Venezuelans wondering if Guaido's moment has passed.

Guaido on Sunday said the opposition-controlled congress would investigate alleged wrongdoing within its ranks after website reported that nine opposition lawmakers had advocated for a businessman linked to Maduro's government.

To a dozen Venezuelans interviewed around the country, the scandal has marked another blow to Guaido's reputation and to their hopes of seeing the back of the deeply unpopular Maduro, who has presided over a five-year economic crisis and an expanding authoritarian state.