Late in the day, there were published reports that the Saudis were preparing to concede that Khashoggi, a USA -based Saudi contributor to The Washington Post, had been killed in an interrogation gone wrong.
There was also a suggestion they had meant to abduct Khashoggi and take him to Saudi Arabia.
One source says the report will likely conclude that the operation was carried out without clearance and transparency and that those involved will be held responsible.
The CNN report comes hours after President Donald Trump told reporters that King Salman of Saudi Arabia strongly denied his government had any involvement in Khashoggi's disappearance and said "rogue killers" could be responsible.
Turkish officials believe Mr Khashoggi was murdered in the consulate by Saudi agents almost two weeks ago but Riyadh has always strongly denied this.
A Department of Foreign Affairs and Trade spokesman confirmed Australia's ambassador to Saudi Arabia and Austrade's general manager for the Middle East would attend.
In a statement published by the state-run Saudi Press Agency, the kingdom warned that if it "receives any action, it will respond with greater action, and that the kingdom's economy has an influential and vital role in the global economy".
The White House is brushing aside threats by Saudi Arabia that it may economically retaliate for any USA punitive action imposed over the suspected murder of journalist Jamal Khashoggi, pledging a "swift, open, transparent investigation" into his disappearance.
Saudi Arabia's sovereign wealth fund, the Public Investment Fund, which hosts the conference, invested $3.5 billion in Uber in 2016, making it one of the company's largest investors.
Samantha Markle Turned Away By Kensington Palace Security
Weird pictures show Samantha clutching a Harry mask that she bought from a souvenir shop after refusing to leave the Royal area. Kensington Palace declined to comment.
Former Trump lawyer Michael Cohen returns to Democratic Party
Trump also celebrated Kavanaugh's appointment amid Democratic opposition and sexual misconduct allegations against the nominee. He talked about exiting the Iran nuclear deal and drew wild applause for mentioning his plans for a Space Force.
Hurricane Michael devastated Mexico Beach
The death toll was revised to 2,975 fatalities, either in the storm itself or later as the health care and utilities grids failed. Brock Long , head of the Federal Emergency Management Agency (FEMA), said early evacuation efforts in the area were slow.
Turkish officials have said they believe Khashoggi - a Washington Post contributor who was critical of Prince Mohammed's policies - was killed inside the mission, and lurid claims have even been leaked that he was tortured and even dismembered.
Mr Pompeo was hastily dispatched to Riyadh amid signs that the current Saudi position - a flat denial that Mr Khashoggi was killed inside their consulate in Istanbul - might be about to change.
"It has been 13 days since the event, so surely proving some of the evidence might be difficult" the Turkish official said.
But he has said repeatedly that he does not want to halt a proposed $110 billion arms sale to Saudi Arabia - as some in Congress have said he should - because it would harm the USA economically.
Earlier, US President Donald Trump threatened "severe punishment" if it is determined that Saudi Arabia is behind the journalist's disappearance. Permission apparently came after a late Sunday night call between King Salman and Turkish President Recep Tayyip Erdogan.
Alphabet Inc's Google on October 15 became the latest company to say it would boycott the Future Investment Initiative Summit scheduled to be held in Riyadh starting October 23.
Saudi Arabia and its allies, however, are pushing back. An Endeavor spokesman declined to comment on the report. Executive Chairman Bill Ford.
Khashoggi was once a prominent member of the Saudi kingdom and a top adviser to the royal family.
Similar campaigns trended on social media in Saudi Arabia and the United Arab Emirates.