Qatar's foreign ministry said in a post on its official Twitter account that Saudi Arabia had only granted an entry permit to Public Health Minister Hanan al-Kuwari after the meeting at the Gulf Cooperation Council (GCC) General Secretariat on Wednesday had already started.
"We are surprised to see that Saudi is politicizing a humanitarian sector, that requires close collaboration and coordination due to the urgency of the situation," the English-language statement issued on Thursday said.
The secretariat and Saudi Arabia's government media office did not immediately respond to Reuters' requests for comment.
Saudi Arabia, the United Arab Emirates, Bahrain and non-GCC Egypt have imposed a political, economic and trade boycott on Qatar since mid-2017 over allegations it supports terrorism and is cozying up to regional foe Iran. Doha denies the charges and says the embargo aims to curtail its sovereignty.
The first glimmer of a thaw had appeared late last year when Saudi Arabia and Qatar began talks over the dispute, but Qatar's foreign minister said last week the discussions did not succeed and were suspended at the start of January.
Kuwait and the United States, which has strong ties with all the states involved, have tried unsuccessfully so far to mediate in the row to restore Gulf unity. Washington sees the rift as a threat to efforts to contain Iran.
There have been nine confirmed cases of the new coronavirus in the UAE, which is a major international air transport centre and regional tourism and business hub. Most of the people infected have been Chinese nationals.
The epidemic originated in China and has killed more than 2,100 people there. New research suggesting the virus is more contagious than previously thought has added to the international alarm over the outbreak.