Wirtz joined the Reds last year in a deal that could reportedly rise to £116 million, but has so far struggled to adapt to the physicality of the Premier League.
The German international, who rose to stardom during Bayer Leverkusen's unbeaten run to the Bundesliga title in 2022/23, has scored just seven times in 56 appearances for Liverpool.
Barcola is only six games into his Liverpool career since a £123 million switch from Paris Saint-Germain, but is yet to score or assist for his new club.
"I think they've had good games and bad games this season, like everyone else, but they are two players that we know their level and they will give us for sure good performances," Iraola said ahead of his side's Champions League trip to Austrian champions LASK.
The former Bournemouth manager believes Barcola's display in a 3-0 defeat by Manchester City at Anfield on Sunday would have been viewed differently had Lewis Koumas netted from his pass when the game was still goalless early in the second half.
"I was happy with a lot of things the other day with Bradley," added Iraola. "He had good situations, we just didn't finish them but him and Flo are players that I trust 100 per cent."
There is even more scrutiny on Barcola and Wirtz, with Alexander Isak, Cody Gakpo and Dominik Szoboszlai sidelined by injury.
None of the three has made the trip to Austria, but Iraola hopes they will be back swiftly.
"They are not far, but it's difficult to tell you right now," said Iraola.
Liverpool travel to Brentford on Sunday before hosting Villarreal and Brighton next week.
"I don't know if they're going to be ready for Brentford, for Villarreal or Brighton."