World football's governing body this week opened an investigation and sent a letter to the North Korean football authorities.
It followed new, unspecified evidence brought to its attention by Chung Mong-Joon, the powerful South Korean former chairman of Hyundai, who is also the president of the South Korean Football Association.
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"We sent a letter to the football federation to tell us about their election of a new president and to find out if the allegations made by the media that the coach and some players were condemned and punished are true," said Blatter.
"We are doing this as a first step and we will see how they answer.
"But it is not easy," added the Swiss, who is in Singapore for the Youth Olympic Games.
"We once had a case in another country where it was said players were also condemned and under physical pressure and we sent someone and it turned out not to be true.
"So let's see what we hear before we make an official statement."
North Korea bowed out of their first World Cup since 1966 after an impressive performance during a 2-1 defeat to Brazil in South Africa before being routed 7-0 by Portugal and 3-0 by Ivory Coast.
The showing of live games in the impoverished communist state had been banned to avoid national embarrassment, but after the Brazil game state television made the Portugal match its first live sports broadcast ever.
They could not have picked a worse game, with the hail of goals from the European side leaving the commentator speechless.
According to Radio Free Asia, on their return home team members were made to stand on a stage at the People's Palace of Culture in the capital Pyongyang and were subjected to "ideological criticism" for six hours.
Citing sources in the country, it said around 400 officials including Sports Minister Pak Myong-chol, other athletes and sports students were among the audience.
The players were apparently forced to criticise coach Kim, who was punished for "betraying" Kim Jong-Un -- one of supreme leader Kim Jong-Il's sons and his heir apparent.
The coach was reportedly expelled from the Workers' Party of Korea and sentenced to hard labour on a building site.
Asian Football Confederation president Mohamed bin Hammam travelled to North Korea recently and met several World Cup players, but there was no sign of coach Kim.
He was unable to confirm whether they had been mistreated or publicly humiliated.
"I was actually in North Korea three weeks back and met with four of the players and we had a chat," said the Qatari, who was in Singapore on Wednesday.
"But I haven't heard anything from within.
"There have been reports of course that some players have gone through torture, but personally I cannot confirm this because I have not seen anything with my eyes or heard anything with my ears.
"FIFA decided to have an investigation to clear the air, and possibly clear the North Korean officials, and I support this."
