The minister’s Social Democratic Party (PSD) reported Ben Omar, 55, had died on Sunday at the main hospital in the capital Niamey but did not list the cause.
“Alas, it is this terrible disease which took the life of minister Mohamed Ben Omar,” public television Tele Sahel reported.
Before announcing the news, the channel broadcast a recent message from the minister urging workers to protect themselves from the coronavirus.
“COVID-19 is a reality, it’s not a state of mind. It’s deadly. It kills. It spreads at the speed of light,” Mohamed Ben Omar told the station.
“We must get a grip of ourselves in order to say ‘stop this virus.’ It is discipline alone that will be the weapon to destroy this virus,” he said.
President Mahamadou Issoufou said earlier he had learned the news of his death with a “heavy heart”.
Ben Omar, born January 1, 1965, in the south-central town of Tesker, had led the PSD, which is allied with Issoufou’s Party for Democracy and Socialism.
Issoufou’s labour minister since 2017, Ben Omar began his political life in 1999 under president Mamadou Tandja, serving in parliament or in various ministerial roles in the impoverished Sahel nation.
Ben Omar strongly supported a constitutional amendment that allowed Tandja to prolong his second term by three years in 2009, but a military junta overthrew Tandja the following February.
Before he created the PSD, Ben Omar was part of the Rally for Democracy and Progress, the party of Tandja’s predecessor Ibrahim Bare Mainassara, who was assassinated in 1999 by members of his own bodyguard.
Niger has recorded 755 infections of the novel coronavirus, with 37 deaths.
The country has already declared a state of emergency as well as closed its borders, places of worship and schools. It has also cut off the capital from the rest of the country.