Samsung Electronics has extended the refund deadline for the Galaxy Note 7 to September 30, as new batteries have been required to go through X-ray testing.
The refund deadline was initially September 19, announced in the company's recall announcement for the handsets due to battery explosions.
But following orders from Korean Agency for Technology and Standards, new batteries produced by Samsung SDI for Galaxy Note 7s must now also go through X-ray testing before being shipped.
Samsung Electronics will conduct additional testing for safety once the batteries are delivered.
Since the exchange began on Monday, around 100,000 units have been exchanged in South Korea. Samsung sold around 400,000 before the recall in its home country.
The exchange will last until March next year, and the company expects the recall will be nearly completed by the end of the month.
Official sales for the handset will began in South Korea on September 28, and early October in the US.
Analysts expect the recall and halting of official sales to cost Samsung an 8 percent decline in profits for the third quarter.