NMS Director-General Mohamed Badi said the hackers were City Hall staff who collude with outsiders to do the illegal approvals.
He said some of the hackers have since been arrested after the Directorate of Criminal Investigations (DCI) was alerted with the investigations still continuing.
“The hacking paved the way for illegal building approvals to be made and there were 18 illegal approvals done when the system was hacked into, forcing us to suspend it,” said Mr Badi.
“The hackers are not strangers or outsiders but retired county staff who had access to the system and are now working with outsiders to do illegal approvals. It’s unfortunate that desperate city residents landed in the hands of these conniving dealers and got illegal approvals,” he added.
Mr Badi made it clear that NMS will not allow the construction of buildings which have not been approved by the Nairobi City County Urban Planning Technical Committee.
“City residents have suffered in the hands of conmen but unfortunately as NMS we will not allow a single building to go up without the proper approval by the technical committee on urban planning. We shall go for it and bring it down,” he said.
However, the NMS boss said they have now sealed the loopholes after bringing in experts from the Ministry of ICT as well as security agencies.
“We handed over the e-construction system to the experts to look into the situation. It took us almost two weeks to close those loopholes,” said Mr Badi.
Last week, NMS suspended approval of development plans in Nairobi after the Quick Response (QR) code system, which is part of the e-construction development plans application system used for the application of building plans and construction permits, was hacked into.
The online QR code system provides a unique identification of all approved architectural and structural plans, eliminating the need for property developers to submit hard copies of development plans for stamping upon approval.