An Aussie man has stopped two alleged teenage thieves in a dramatic early morning citizens arrest. 

Alarm bells rang for Bradley Cowper, 29, when a Hyundai iMax van overtook him at speed while driving on the Gold Coast early on Boxing Day.

He decided to follow the van, which was allegedly driving erratically at speeds of up to 120km/h and almost hit a cyclist.

When Mr Cowper caught up to the van at traffic lights in Ashmore, he spotted two boys inside were wearing face masks and gloves. 

He sprung into action and approached the van, managing to open the driver's door.

The van mounted the median strip and sped off in the wrong direction.

Mr Cowper told the Gold Coast Bulletin he lost sight of the vehicle before he spotted the damaged van and the youths 2.6km away in Warrungen Way after the car allegedly hit the kerb.

He will never forget the 'petrified' look on the teens' faces and how one 'started begging for his life'.

'I'm 6ft 4 (193cm), and I was running towards (one), and his face was priceless, like he'd seen a ghost',' Mr Cowper told the publication.

'The one the other guy (detained) kept saying sorry, he was like "My mum's gonna kill me, this is the first time I've ever done anything illegal".'

Two other nearby residents and an off-duty police officer helped Mr Cowper detain the pair until the cops arrived.

Police allege the van was stolen from the Brisbane suburb of Hendra 80km away several days earlier.

A 13-year-old from Bellmere and Upper Caboolture 14-year-old were charged with unlawful use of a motor vehicle and will appear in Southport Children's Court at a later date.

Mr Cowper has no regrets about intervening. 

'If no one does anything, nothing will happen. Who's going to stop (them)?' he said.

It follows a spate of juvenile car thefts and break-ins on the Gold Coast over the Christmas period.

Hours earlier on Boxing Day, construction worker Steven Middleton fought off a gang of five alleged  car thieves wearing nothing but his underwear.

He was up early for a fishing trip when he saw someone ransacking his car.

Mr Middleton was captured on CCTV rushing outside to confront the alleged thieves and gripped the shirt of them before his accomplices attacked him with a baseball bat and a knife.