Rafael Nadal has rejected suggestions professional tennis is getting easier for the older generation after three players over the age of 30 reached the Australian Open semi-finals.

The Spaniard booked the final place in the last four on Wednesday with a straight-sets victory over third seed Milos Raonic, joining fellow veteran Roger Federer and Stan Wawrinka in progressing.

His next opponent - Grigor Dimitrov - is the youngest of this year's semi-finalists at 25, but Nadal does not believe the exertions of the tour are taking less of a toll on the elder statesmen.

"I think is getting tougher now," he told a media conference.

"I think now there is really a new very good generation. Probably few years ago things were a little bit different, but now there's lot of good young kids.

"It's going to be tough to make that [four semi-finalists over 30] happen again."

Nadal has a superb record against Dimitrov, with seven wins from their eight meetings. Despite that advantage, he still expects a difficult encounter in the semis.

"He's a player that [has] been on the tour for a lot of years already," he added.

"He's a player that has an unbelievable talent, unbelievable potential. He started the season playing unbelievable.

"It is going to be a very tough match for me. I hope for him, too. I going to try to play my best because I know he's playing with high confidence."