Next time you're lying on the couch in your undies watching television, remember the City of Cape Town might be watching you.

City officials shocked Western Cape parliamentarians yesterday when they revealed that, for the past seven years, the municipality had been using cameras able to zoom into homes and other properties to the extent that they can see the set-up of residents' bedrooms.

This was revealed by a city delegation, led by Christopher Gavor, at a meeting of the province's local government portfolio committee.

They explained that three-dimensional images of Cape Town houses and buildings were captured for property valuations.

It was not clear if drones were used to obtain the images, but officials said the images were far more invasive than Google Street View.

The city uses the images to assess the dimensions of buildings, and the extent to which the land on which they are built slopes.

With house plans and the images, officials can determine how many rooms the house has, their locations and size.

"So, without us having to physically inspect a property, sitting behind my computer in the office I can see your house," said Themba Musekiwa, head of data services.

It was this detail that got the MPLs fired up and prompted to them ask about the security of the data collected and the possibility of it being used illegally.

DA MPL and former Western Cape police chief Lennit Max called the technology a "spycam".

"Is that legal spying? Are they not encroaching on my privacy?" asked Max.

Gavor said the city was allowed by law to use the technology and gave the assurance that the images would be regarded as confidential.

"It's true that we have every detail of your house, [including] the number of bedrooms, the quality of your bedroom [and] the view from the sea," he said.

ANC MPL Richard Dyantyi asked if there had ever been an instance of a city official being caught using the "spycam" for criminal activities, such as supplying information to house-breaking gangs.

Committee chairman Masizole Mnqasela said he was worried about the safety of the data in the city's possession. He asked whether the officials who had access to it had been vetted and given security clearances.

Gavor said the officials took an oath and if they were found to have misused the information they could be prosecuted.