"We have a few issues with some players in our squad with a minor flu," Ghotbi told reporters on Friday before they face the Koreans at the Qatar Sports Club on Saturday.
"It started really with the beginning of our training camp with our captain, then I had the flu for several days and it has gone through two, three, up to four players at a time."
Victory for Iran would book a place in the quarter-finals of the 16-team premier Asian tournament but they face the tricky task of breaking down a defensive-minded North Korean side.
The Koreans have not conceded a goal in their last three outings and have reverted back to a 'defensive first, attack second' strategy after being humbled 7-0 by Portugal in the World Cup finals in South Africa last June.
"I hope North Korea plays like they did against Portugal in the World Cup when they were open and attacked," Ghotbi said.
"But I think they will play very closed and attempt to counter attack which is why it is important we score early to bring them out of their shell."
MENTAL TOUGHNESS
Three-times champions Iran will start as favourites for Saturday's match following their comeback victory over holders Iraq in their opening game but Ghotbi said there was little time to bask in the adulation of victory over their rivals.
"To be champions of a tournament you have to play six matches in 18 days and it takes a lot of mental toughness, discipline and quality to be able to recover."
"We tried to enjoy the victory (over Iraq) in the first 24 hours and immediately we started focusing on the next match.
"I think our players are up for the challenge of playing North Korea and realise by gaining the three points they can reach the first target of getting out of the group."
The Koreans were fortunate to claim a 0-0 draw with the United Arab Emirates in their opening match and will need a big improvement if they are to beat Team Melli for the first time at their 17th attempt.
"We played one match against UAE and our analysis was we didn't play well in the first match, 0-0 was not our expectation and we will try to do better for the next two matches," North Korean coach Jo Tong-sop said.
"The UAE team played with good individual skill and we tried to put more emphasis on the defense."
Iraq will play the United Arab Emirates at the Al Rayyan Stadium also in Group D on Saturday.
