A statement posted on the website of President Thein Sein said an OIC office would be going against the wishes of the people, a report by the British Broadcasting Corp. said.
"The government will not allow the opening of an OIC office as it is not in accordance with the desire of people," the website notice said.
But the 57-member OIC, which recently visited Myanmar, told the BBC it hadn't been notified of the president's decision, the BBC said.
Myanmar is not a member of the OIC.
On the weekend thousands of Buddhist monks marched in Yangon to protest the opening of an OIC office.
The government notice appeared soon after the protests,
When violence erupted between Buddhists Rakhines and Muslim Rohingyas in early June, the government was quick to move in troops.
Rakhine, formerly called Arakan state, occupies most of Myanmar's west coast on the Bay of Bengal and has a relatively large Muslim population. Within Myanmar, Buddhists make up 89 percent of the population while Muslims and Christians make up around 4 percent each, United Nations estimates state.
Rakhine state also is home to Rohingya, Muslims with close ties to neighboring Bangladesh.
The violence began in May after a Buddhist woman was raped and murdered by three Muslims.
A mob later killed 10 Muslims in retaliation.
The government estimated that 77 people from both communities lost their lives in the ensuing riots, mostly in Sittway, Maungtaw and Buthidaung townships.
More than 100 people were injured and nearly 5,000 homes, 17 mosques, 15 monasteries, three schools were burnt down, the government said.
Thein was quick to go on national television in June after the riots to ask for calm and said the government would set up a commission to look into the reasons for the violence.
A government statement at the time said the violence wasn't because of religious persecution but "due to mistrust and religious differences that had created hatred and vengeance against one another."
Because people from both communities were killed, "it is very clear that the riots aren't linked to religious persecution. Myanmar is a multiracial and multi-religious country where people of different faiths have lived together in peace and harmony," the government statement said.
But the violence created a tide of refugees across the border into Bangladesh, as well as within Myanmar.
The U.N. High Commissioner for Refugees estimated that around 80,000 people have been displaced in and around the Rakhine towns of Sittwe and Maungdaw where much of the violence took place.
"Most of them are living in camps for internally displaced people, with smaller numbers staying with host families in surrounding villages," the statement said.
The government said it is working with aid agencies including the UNHCR to build and improve camps and with the World Food Program to feed displaced people.