Samsung has revealed why one of its flagship smartphones, the Galaxy Note 7, was catching fire, but experts say questions remain over the company’s response.

Samsung Mobile chief DJ Koh told a press conference that a design flaw had caused the first batch of phones to short circuit.

A welding defect during manufacturing had doomed the replacement run amid a rush to release the updated version.

The company built a standalone testing lab and gathered more than 700 researchers and engineers to test 200,000 devices and 30,000 batteries, Mr Koh said.

Samsung launched the Note 7 on August 19, 2016, with the first reports of exploding phones surfacing later that month.

Customers were issued with replacement phones later that month, but on October 11 sales were permanently halted over continued reports of phones catching fire.

Earlier this month, the company said 95 per cent of Note 7s has been returned by Australian customers.But the controversy has caused continued embarrassment for Samsung.

Air safety authorities in Australia and the US have mandated that airlines remind passengers about the dangers of the Note 7 onboard the plane.Mr Fadaghi said the Note 7’s battery woes had handed an advantage to other Asian manufacturers and Google, which has entered the market with its Pixel smartphone.