Lagos emergency management agency says the building was being worked on by "unskilled labourers" when it collapsed.

An unknown man has died following a building collapse in the Ikeja area of Lagos.

Olufemi Oke-Osanyintolu, the Permanent Secretary, of Lagos State Emergency Management Agency, in a brief statement on Thursday, said the deceased was a welder who was in the one-storey building at the time of the incident.

"The Agency responded to distress calls and upon arrival, discovered that a storey building formerly occupied by KILMS MART, was being worked on by unskilled labourers resulting in a partial collapse," the statement reads.

"An adult male reported to be a welder lost his life instantly at the scene. His remains were recovered and removed from the scene.

"The post-disaster assessment conducted by the Agency's LRT indicates that the building is stable and does not pose a threat to other buildings around.

"The building has been cordoned off and LASBCA and Nigeria Police have been contacted for further action."