Around 2 800 households in the Johannesburg central business district remain in the dark as officials work to restore services following an explosion that rocked Lilian Ngoyi Street (formerly Bree Street) last week.

City manager Floyd Brink said water and power had yet to be restored because some parts of the CBD had not yet been declared safe.

"We request residents to be patient with us. We will continue providing them with water and servicing our mobile chemical toilets."

City Power spokesperson Isaac Mangena said: "We will switch on once the disaster management, Department of Labour and EMS give us the go-ahead. About 2 800 households are affected."

Mayor Kabelo Gwamanda, Brink and other officials conducted an inspection at the site on Monday afternoon.

Sections of Lillian Ngoyi Street were ripped up when a gas blast rocked the busy city centre during the afternoon rush hour on Wednesday.

The blast killed one person and injured 48 others.Gwamanda said they could not speculate about which entity would be held responsible.

The mayor said it was still unclear how pipelines from Egoli Gas, City Power and Joburg Water could have contributed to the explosion. 

He said the executive was on site to ensure resource availability and to assess whether what was being communicated, in terms of investigations and repairs, was being implemented on the ground.

Gwamanda said the role of the executive was to oversee without "overreaching" and that he could not pre-empt the outcome of the investigation.

Meanwhile, Brink warned that the city would arrest and impound vehicles driving through the barricaded site along Lilian Ngoyi Street.

"From tomorrow [Tuesday], there won't be any tolerance for those who disobey our officers. Motorists who drive through our barricades will have their vehicles impounded," said Brink.

He also warned pedestrians not to walk into the site. Some were seen strolling along and standing above the cracked tar road, taking pictures.

Community Safety MMC Dr Mgcini Tshwaku echoed Brink's warning.

"Anyone who walks or drives in the barricaded area will be arrested and charged. This is now a construction site. We have JMPD pushing onlookers away from the site. We don't have a problem with those walking in designated areas," he said.

Tshwaku claimed the city had the expertise to fix and restore the street.

"The matter is in the hands of investigators. We don't want to hurry people. There will be a simulation that [will] take place. After that construction will begin," Tshwaku said.

The city called for calm and patience.