Gaga claimed her Peru show had an audience of 50,000, whereas actual ticket sales were reported to be around 17,000, with many tickets for the show being given away free as part of a buy-one-get-one-free deal.
Many of Gaga's Latin American shows also suffered from similarly low turnouts. However, Madonna regularly played in the same area to sold-out crowds of more than 55,000.
Gaga's tours have fared much better in Europe and South Africa, and the she is set to launch her Born This Way Ball tour in North America next month.
The singing stars have been engaged in a feud after Madonna began bringing attention to the similarities between her song Express Yourself and Gaga's Born This Way on her most recent tour.
Gaga was also reported to have turned down an offer to perform with Madonna on the MDNA tour.