Wilder has a 39-0 record and is set to fight Louis Ortiz in March.
He told Yahoo Sports that he expects a close bout between Parker and Joshua.
"I definitely think that's a 12 round fight. I like Parker. I like Joshua as well too. The thing about Parker is that he moves well too. We've seen he can take some great punches. We know for a fact that Joshua's last opponent Takam, that Joseph Parker beat him so we know he can take a punch," Wilder said.
Read more: Joseph Parker and Anthony Joshua bout close, but not over the line yet, Eddie Hearn says
However Wilder added that Parker (24-0) has yet to really be tested.
"…but we haven't seen Joseph fight against a guy that's thrown, that throws a nice punch. We haven't seen Joseph Parker take a nice punch on the chin so we really don't know that about him."
Despite that Wilder, who is expected to fight the winner of Parker-Joshua later in the year, said the fight will go long with Joshua desperate to make a statement.
"I think it's going to be a hell of a fight while it lasts. I think it's going to be a long drawn out fight. Both will have to feel each other with different movement. Parker's going to have to stay out of the way of Joshua. I know Joshua is going to try and make a statement, he's going to try and redeem himself from the last fight and try and get him out of there. It's a wonderful fight."
"Everyone wants to see unification bouts so I can't wait for that."