The Food and Environmental Hygiene Department (FEHD) released a statement expressing "profound sadness" over the death of the outsourced cleaning service contractor, reports Efe news.
The man was hit during his lunch break near North District Town Hall on Wednesday.
"We have requested the service contractor to follow up the labor insurance and compensation matters promptly," said an FEHD spokesperson, according to the statement which added that the police would do everything to investigate the case and bring the "offenders to justice".
Since the first day of the general strike on Monday, Hong Kong has witnessed a sharp rise in violence with demonstrations ending in clashes that have resulted in several people injured.
On Wednesday, two people were reported to be seriously injured a 15-year-old who was hit in the head by a tear gas canister, and the now-deceased 70-year-old man.
On Monday, a 21-year-old boy was shot by a traffic policeman and in a separate incident, a 57-year-old was set alight after a political argument.
The young man's condition improved from critical to serious and has reportedly been arrested for unlawful assembly, whereas the man set alight remains critical with burns to 44 per cent of his body.
On November 8, a 22-year-old student died after being in a coma for several days after falling from the third to the second floor of a parking lot in a building situated near clashes between the police and protesters.
The circumstances around his death remain unclear.
Continued protests and clashes between demonstrators and riot police at several campuses of educational institutions in Hong Kong has led several universities to announce an early end to the semester on Thursday.
The demonstrations, which have drawn massive crowds since June following a contentious proposed extradition law, have turned into a movement seeking to improve democracy in the city-state and safeguard the region's partial autonomy from Beijing.
Some demonstrators have opted for more radical tactics than peaceful civil disobedience and violent clashes with the police have been frequent.
( With inputs from IANS )