Nigeria's transport minister said Friday that completion of a key railway project has been delayed by the coronavirus outbreak as Chinese workers had not returned to the country. The 150-kilometre (90-mile) railway line linking economic hub Lagos to the city of Ibadan is being built by the state-owned China Civil Engineering Construction Corporation. "Most of the Chinese workers who went on their New Year holiday have not yet returned due to the coronavirus and this has delayed the work," minister Rotimi Amaechi told AFP. The $1.5 billion project -- preliminarily scheduled to be completed in May -- has faced repeated delays since it was first agreed back in 2012. The novel coronavirus has infected over 100,000 people and killed more than 3,400 since the outbreak emerged in December in the Chinese city of Wuhan. Beijing has ploughed billions of dollars into building infrastructure across Africa as it has bolstered its influence on the continent. Sub-Saharan Africa has so far been relatively lightly impacted by the spread of the virus despite its deep business links with China. Nigeria -- the continent's most populous country -- has reported just one case, an Italian man who travelled to Lagos from Milan. Senegal has registered four cases, while South Africa, Cameroon and Togo also have once case each. del/dl