A 4-1 win at Nuremberg clinched fifth place in the Bundesliga and an automatic berth in the group stage of the Europa League next term, and Voller hailed the duo's contribution.
After taking over from Robin Dutt on April 1, Hyypia and Lewandowski guided the club to an unbeaten run of four wins and two draws from six matches.
"When you pick up points like that, then it is a positive argument," Voller was quoted as saying by Kicker magazine.
"And when you also see how the pair were accepted by the team, then you can imagine continuing with both of them."
Leverkusen have been in no rush to find a permanent successor for Dutt, but now the season is over and they know what competitions they will be playing in next season, the search can start in earnest.
"It would be negligent of us not to consider other options," added Voller.
"We will now analyse things in depth."
Meanwhile, the future of Leverkusen forward Andre Schurrle is also up for discussion amid rumours of interest from Chelsea.
The Germany international told Sky that he had received no enquiry from the Blues, but hinted he would be open to a move to the Premier League club, who signed his international team-mate Marko Marin last week.
"I and my agent have not had any contact so we will just have to wait," he said.
"We will see how interesting it is when it becomes concrete."