Though there has been no official announcement about the December 18-21 summit, the source said on Monday that Pakistan will be "represented at the summit by Foreign Minister Shah Mehmood Qureshi", The Express Tribune reported.
According to the Malaysian news agency Bernama, Mahathir devised plans for the summit while meeting with the leaders of Pakistan and Turkey at the UN General Assembly in September.
On November 23, he announced that his country would host the summit in December.
Meanwhile, Special Assistant to the Prime Minister on Information and Broadcasting Firdous Ashiq Awan said that the decision to attend the summit would be taken "in accordance with national interests".
"The Prime Minister is currently in Bahrain and will later visit Geneva. He will return to the country on Wednesday and (the government) will then decide if he should visit Malaysia," she told reporters on Monday.
Khan had earlier confirmed his participation in the summit, which will also be attended by leaders of Turkey, Qatar and Iran.
Around 450 leaders, scholars, clerics, and thinkers from 52 countries are also expected to attend the event.
However, according to the media in the Middle East, the summit is seen as an attempt to create a new bloc in the Muslim world that could become an alternative to the Organisation of Islamic Cooperation - an idea that upsets Saudi Arabia.
( With inputs from IANS )