Salah has been one of the standout performers in the Premier League this season and is the top scorer with 16 goals so far.
The forward's performances have seen him nominated for The Best FIFA Men's Player of the year award for 2021 alongside Messi and Bayern Munich striker Robert Lewandowski.
Salah turns 30 in June, and when asked at a news conference on Wednesday whether the Egypt international can produce similar levels to Ronaldo and Messi in the latter stages of his career, Klopp replied: "Yes, I think so.
"It's his character, determination and that's the way he trains. His work attitude is incredible, he's the first in and last out, doing the right stuff.
"He knows his body, he knows what to do, he's listening to the experts here and tries to improve all the time. He works so hard for the situation that he's in now and will not waste it by doing less. So yeah, I'm as convinced as you can be."
Klopp was also asked about Salah's comments in GQ magazine on Tuesday where he said: "I'm not asking for crazy stuff" regarding talks over a new contract with the club.
"Nowadays it's dangerous with these interviews," Klopp said. "We know, I know, that Mo wants to stay. We want him to stay. That's where we are. These things take time, I cannot change it. It's all in a good place.
"There are so many things in negotiations," he added. "It's a third party too, with the agent. It's nothing to worry about, it's a normal process.
"I am positive about it. The fans are not as nervous as you are. They know the club and know the people dealing with things here. We cannot say anything about it."
Liverpool will be without Salah and Sadio Mane, who are on international duty at the Africa Cup of Nations. Klopp confirmed that Trent Alexander-Arnold was back in contention for the match but that Thiago and Divock Origi were still unavailable.