Fears of a renewed outbreak of war by the United States and Israel against Iran have risen again in recent weeks.
Munir has previously mediated between the Iranian leadership and the US.
On Monday, US Defense Secretary Pete Hegseth made a surprise trip to Israel, meeting Prime Minister Benjamin Netanyahu at an air force base in the south of the country.
The media reported that Iran has held military exercises and missile tests in recent weeks.
Russian Foreign Minister Sergei Lavrov was also in Tehran for talks on Monday.
"Never in our history have Iran and Russia worked as closely as now," his Iranian counterpart Abbas Araqchi wrote on X after the meeting.
Iran is also hoping for military support from Russia in its conflict with the US.
The visits by Lavrov and Munir should be considered the start of a Russian de-escalation initiative for the region, Pakistani intelligence sources told the DPA news agency.
The talks concern both a possible agreement between the US and Iran, and the conflict in Yemen between the Iran-aligned Houthi militia and Saudi Arabia.
As an ally of Saudi Arabia, the Pakistani negotiator is to convey a message to the government in Iran.
"Munir will tell them that the Houthis' aggression could also drag Pakistan into a conflict with Iran," an intelligence officer told the DPA news agency.
The US and Israel attacked Iran at the end of February.
Several nearby countries, including Qatar and Oman, have been seeking de-escalation since then.
Pakistan successfully worked earlier this year on a framework agreement that was meant to bring a lasting solution to the conflict.
However, the agreement did not last.
The conflict is currently focused on the Strait of Hormuz.
High petrol prices following restrictions on energy trade are putting pressure on US President Donald Trump ahead of his country's midterm elections.
The Iranian government continues to distrust the prospect of talks with the US, partly because attacks occurred in the past while representatives of both countries were in negotiations.
"The United States' record of breaking agreements is clear," Iranian Foreign Ministry spokesman Esmaeil Baghaei said on Tuesday.
"But we, as a diplomatic service, must not neglect our duties solely because of the bitter experiences of the past."
with Reuters
