The victim was pronounced dead at the scene at the River Gardens site in Greenwich.
A Met police spokesman told the Standard: “Police were called at around 17:25 on 11 July to a seriously injured man on a construction site in Christchurch Way, SE10.”
“Police officers are investigating alongside the Health and Safety Executive.”
The final phase of the River Gardens site contains 252 apartments across five blocks of up to 11 storeys.
Bellway said: “We are deeply saddened by the tragic accident and our thoughts are with the friends and family of the deceased man at this sad time.
“We are working with the authorities to understand what happened. It is not appropriate for us to say anything further at this stage”.