San Francisco officials are still unable to access the FiberWAN computer system after a rogue computer technician deleted administrator passwords.

Terry Childs made the changes to the system, which hosts 60 per cent of the city government's data, after a run-in with the head of security.

All administrators are locked out except Childs who is refusing to divulge his access code.

"There is nothing to be alarmed about, save the inability to get into and tweak the system," Mayor Gavin Newsom told the San Francisco Chronicle. "Nothing dramatic has changed in terms of our ability to govern the city."

The system is currently running well and documents can be accessed, but there will be no way to quickly effect repairs if the system crashes.

Newsom said that engineers from Cisco had been brought in to try and gain access and that, if necessary, the city could rebuild it from scratch.

Newsom added that, until recently, Childs had been considered a highly regarded member of staff but was now a "rogue employee that got a bit maniacal" .

"He was very good at what he did, and sometimes that goes to people's heads, " he said. "We think that is what this is about."

The trouble started on 20 June when the new head of security began an audit of who had access to FiberWAN. The head of security said that Childs began taking pictures of her, and that she was forced to retreat to her office.

It was then discovered that Childs had put spyware onto the system so that he could monitor any emails sent by his superiors about him.

It is believed that he escalated the situation last weekend when he locked out all administrators but himself.

Childs has been charged with four counts of misusing computer systems and is back in court tomorrow. He is being held on $5m bail, a tariff his attorney Mark Jacobs has called "crazy".

"I do not think he is a threat," Jacobs said. "He did not kill anybody, and murderers usually get a $1m bail, so you do the math. Someone out there is really scared of something, and I do not know what that is."

It has also emerged that Childs has a criminal record for aggravated burglary, for which he served five years probation in 1982.