Callamard briefly visited the Istanbul neighbourhood where the Saudi consulate is located but did not enter the premises.
Last week, Cavusoglu said it was time to open a UN-led investigation, adding that President Recep Tayyip Erdogan had ordered the relevant preparations.
Ahead of Ms Callamard's visit, Turkish Foreign Minister Mevlut Cavusoglu said it was high time for an worldwide inquiry.
The expert on extrajudicial, summary or arbitrary killing said she would present her report in June to the U.N.'s Human Rights Council and the report would be made public ahead of the meeting.
On Tuesday the team is also scheduled to meet with Istanbul's chief prosecutor, Irfan Fidan, who carried out a criminal investigation on the murder and asked for the extradition of suspected members of the hit squad believed to have killed the reporter. "We are respectfully asking the authorities to give us access at some stage". "Justice must be served", wrote Fahrettin Altun, referring to an alleged local who may have been involved in the disposal of Khashoggi's body, which has yet to be found.
Khashoggi, a Washington Post columnist who wrote critically about Saudi Crown Prince Mohammed bin Salman, entered the Saudi Consulate in Istanbul on October 2 to obtain documents for his upcoming wedding.
Callamard, a French academic who is the director of the Columbia Global Freedom of Expression Department at Columbia University in NY, reports to the U.N. Human Rights Council in Geneva and has a global mandate to investigate executions.
Saudia Arabia's uncooperative approach has been consistent since the day Khashoggi was murdered.
Ankara has used every means available to bring those responsible to justice, while maintaining global pressure.
Turkish officials have been frustrated over what they say is a lack of cooperation by Riyadh and has called for an worldwide inquiry. "We made a request to the Saudi government for access to the consulate, as well as meeting with Saudi authorities here and in Saudi Arabia", she said.
The CIA, however, has concluded that the 33-year-old heir to the Saudi throne nearly certainly signed off on the operation.