Kiessling won the golden boot award in the Bundesliga last term with 25 goals, yet the most recent of his six international caps came almost three years ago.
He was overlooked by Joachim Low for a post-season tour of the United States, even though the Germany coach acknowledged his goals and performances had not gone unnoticed.
With a chance to underline his talent in the UEFA Champions League next season, Voller believes Kiessling will be going to Brazil next summer.
"If he plays another year like this, then Jog Low is not going to get away with ignoring Stefan," he said to the Bild newspaper.
"He must not give up hope. I certainly continue to believe in his chances of going to the World Cup."
Kiessling has yet to open his account for Germany, although the 29-year-old is just two short of a century for Leverkusen.
In a total of 293 appearances in the top two divisions of German football, Kiessling has scored 113 times.