Less than half of the 54,000 tickets have been sold for Wednesday's friendly against fellow World Cup finalists Ivory Coast in Gelsenkirchen.
"Obviously this date at the end of the year is one of the reasons (for low sales)," Bierhoff told reporters, adding that the global economic crisis was taking its toll on ticket sales.
"People will think about spending more money shortly before Christmas," he said.
"But we must also return to the level where we offer good performances and excite the spectators also in the friendly matches we stage."
Germany will play for the first time since the suicide of national team keeper Robert Enke last week. The friendly against Chile was cancelled on Saturday and players will wear black armbands on Wednesday.
"It was right for the team to mourn... but we do not want to overload the match on Wednesday with it," said Bierhoff.
"We want to return to our everyday sporting business and enjoy play football because we love it. It would also have been Robert's wish to play with vigour in this match."
Germany will be without captain Michael Ballack, who is suffering from a minor knee injury, with Philipp Lahm taking over as skipper for the match.
Werder Bremen keeper Tim Wiese is expected to start while Manuel Neuer, of Schalke 04, will replace him sometime in the second half, Bierhoff said.
"Neuer will play in the second half in front of his home crowd," Bierhoff said. Bayer Leverkusen striker Stefan Kiessling will also be in the starting line-up.
