The defending champion was hoping to reach a record seventh Australian Open final and enjoyed a strong start against Chung.

Federer broke his 21-year-old opponent in the first game of the match to set the tone for a one-sided encounter.

He strengthened his position further by a second break of Chung's serve, helping the 36-year-old claim the opening set 6-1 on Rod Laver Arena.

It left Chung with an uphill battle in his attempt to become the first South Korean player to reach a Grand Slam singles final.

Chung, who surprisingly beat Serbia's Novak Djokovic and Germany's Alexander Zverev in the early rounds of the tournament, began to struggle through injury in the second set.

He was treated for blisters midway through the set, but was ultimately forced to withdraw from the match three games later, with Federer 6-1, 5-2 up.

"I've played with blisters in the past and it hurts," said Federer.

"At some point, it's just too much and you just can't take it anymore, and when you realise there's no way you can come back and you make things really worse, it's better to stop.

"That's why this one is bittersweet.

"I'm really happy to be in the finals, but not like this."

Federer will now face Croatia's Marin Cilic in the final, as he seeks to join Djokovic and Australia's Roy Emerson in winning the title six times.

Victory would also give Federer his 20th Grand Slam title.

Federer has won his last three meetings with Cilic, including last year's Wimbledon final.

The women’s doubles final took place today, with France's Kristina Mladenovic and Timea Babos of Hungary claiming victory.

The fifth seeds emerged as 6-4, 6-3 winners against Ekaterina Makarova and Elena Vesnina of Russia to claim a first Grand Slam title as a pairing.