Around 100 GT3 models are affected in the UK
Engines in all 785 delivered units of the new Porsche 911 GT3 will be replaced as part of a solution to potential fire issues.
A Porsche spokesman confirmed to Autocar that the problem, which has caused two engine bay fires so far, has been traced to a loose bolt in a piston connecting rod.
"Obviously customer safety is our priority," said the spokesman "We've investigated the two situations and identified that there is a potential for a fixing to become loose and therefore we're rolling out an engine with a modified component. It's much more straightforward to replace an engine than to strip down existing units."
The spokesman said the replacement programme would "undoubtedly" have a large cost attached for Porsche, but added "we don't put a price on our customer safety or vehicle integrity".
In both the reported cases, engine damage in the GT3 resulted in a fire thought to be caused by oil spilling onto hot components. Neither of the fires, which occurred in Italy and Switzerland, lead to any injuries.
GT3 customers have already been told to stop driving their cars. Porsche has confirmed it has written to owners to explain the problem, and is still deciding how best to roll out the engine replacement programme. The manufacturer wouldn't put a time scale on when it expects all GT3 models to be back on the road.
Around 100 units of the GT3 have been delivered to customers in the UK.