DAKAR  - The presidential candidate for Senegal's ruling coalition, former Prime Minister Amadou Ba, warned on Friday that an opponent's proposal to introduce a national currency could discourage investors, a prospect the country could not afford.

"Raising the debate around currency right now causes jitters among investors. Tomorrow, investors are going to wait and see before investing," Ba told journalists in Dakar. "Our economic and social situation does not allow us to create these kinds of uncertainty."

Ba, 62, is facing 18 other candidates in Senegal's presidential election on Sunday. No frontrunner has emerged, but the opposition has seen strong momentum behind Bassirou Diomaye Faye, a 43-year-old former tax inspector.

Faye is supported by firebrand opposition leader Ousmane Sonko, and on Friday received the endorsement of Senegal's former President Abdoulaye Wade and his Senegalese Democratic Party.

Faye has said he will first seek monetary reforms within the eight-nation West African Monetary Union that use the CFA franc. If that fails, he will push for a national currency.

Ba said he would rather seek a monetary union of the 15-nation West African regional bloc. "Our currency is convertible and stable, and inflation has been moderate compared with countries with their own currencies," he said.

Responding to former Wade's endorsement of Faye, Ba said he would continue to reach out to supporters of the Senegalese Democratic Party.

Faye's campaign has drawn widespread support from Senegal's disaffected youth who face high unemployment in a country where the median age is 19.

Ba said that if elected, he would reform the fishing industry to help improve the income of small-scale fishermen. The sector is the country's third-largest employer but Ba said it is in crisis.

Many Senegalese fishermen have embarked on dangerous boat journeys across the Atlantic Ocean to seek a better life in Europe.

(Reporting by Bate Felix; Editing by Cynthia Osterman)