Two office workers enjoying a prime view of Australia's third Test against South Africa made a hasty return to their desks after discovering their cricket break had become part of the broadcast.

The pair were watching the action at Newlands from a neighbouring building when a television cameraman turned his attention away from the pitch.

Zooming in on the offices, he found two men who had rolled their chairs away from their workstations to take advantage of their enviable vantage point.

But their relaxed viewing session quickly ended when they realised they were on television.

Both promptly wheeled themselves back towards their desks, producing a moment that left former South African Test captain Graeme Smith laughing in commentary.

'Back to work boys,' Smith chuckled.

'We should probably establish where they are. They are offices that are on the ground.'

The clip made its way to Reddit, where viewers largely sided with the workers whose sneaky cricket break had been exposed.

'Bro these cameramen are such snitches,' one wrote.

Another argued the pair had found the perfect sport to accompany a day at the office.

'Test cricket is the single best sport in the world to watch while working, I don't blame them,' they posted.

One viewer identifying themselves as a Cape Town local said the scene was entirely in keeping with the city's character.

'As a born and bred Capetonian this is very much Cape Town behaviour!' they wrote.

'Can't blame these guys for avoiding their desk jobs when the crickets on.'

Another commenter offered reassurance that their unexpected television appearance could have been considerably more embarrassing.

'Could have been worse...' they wrote, sharing footage of the infamous Coldplay concert kiss-cam incident.

There was certainly enough happening at Newlands to tempt cricket lovers away from their keyboards, with Mitchell Starc spearheading an Australian fightback on the opening day of the series decider.

South Africa raced to 0-158 after Pat Cummins elected to bowl, leaving the Australian captain facing uncomfortable questions about his decision.

Marques Ackerman made 95 and Aiden Markram contributed 78 before the tourists dragged themselves back into the contest.

Nathan Lyon helped turn the innings with two wickets, including bowling Temba Bavuma for a duck, while Cooper Connolly claimed his first Test scalp by trapping Matthew Breetzke lbw.

Starc then delivered the decisive late burst, taking four wickets in six deliveries with the second new ball as South Africa were dismissed for 329.

The left-armer finished with 6-72, giving Australia a route back into a match that had threatened to slip away during the morning session.

Australia had already suffered a setback before play when Steve Smith withdrew with a neck injury, with Josh Inglis taking his place.