Penev was furious Turkish referee Firat Aydinus missed what appeared to be a handball by Andreas Cornelius just before the Denmark striker was brought down by Bulgaria defender Ilia Milanov for a penalty that the hosts converted to pull level.
"I promised not to talk about the referee's performance but I cannot pass it," former Valencia and Atletico Madrid striker Penev told Bulgarian media.
"Denmark has a very strong handball team and I didn't know that we had to come with our handball national team.
"It's obvious that he (Cornelius) takes the ball with his hand ... and it happened right in front of the referee."
His frustration follows October's 1-1 draw with Denmark in Sofia where his team held on after playing with 10 men for 70 minutes after defender Ivan Bandalovski was shown what Penev at the time called a "disputable" straight red card.
"We've been robbed by referees again. It was a refereeing circus," Penev, who succeeded German Lothar Matthaeus following Bulgaria's dismal Euro 2012 qualifying campaign, said.
"This is not fair play."
Bulgaria went ahead six minutes after the interval on Tuesday when Stanislav Manolev swept the ball home with his third goal of the qualifying campaign. Daniel Agger levelled the score in the 63rd minute from the spot.
"I'm not pleased because we deserved the three points," said 46-year-old Penev, who was once described by former England coach Terry Venables as "one of the top three forwards in the world".
"It'll be good if people in Europe have the possibility to learn how they treat Bulgaria in these qualifiers."
Unbeaten Bulgaria are second in Group B with 10 points from six matches, three points behind Italy. Czech Republic are third on eight points, followed by Denmark on six.