Aerial view of Holland America's cruise ship Zaandam as it entered the Panama City bay to be assisted by the Rotterdam cruise ship with supplies, personnel and COVID-19 testing devices, eight miles off the coast of Panama City, on March 27, 2020.

Nine cruise ships and nearly 8,000 passengers are stranded at sea as major ports deny access to the vessels as the coronavirus continues to spread.

According to cruise tracker site Cruise Mapper, Holland America-operated MS Rotterdam, Coral Princess, MS Arcadia, Cunard Line's Queen Mary 2 are still at sea with passengers and crew members on board.

The Queen Mary 2 is currently sailing back to Southampton and currently has 264 guests on board, according to a spokesperson for Cunard North America. "Most guests disembarked Queen Mary 2 in Fremantle, Australia on March 14 and 15. The ship today made a technical stop in Durban, South Africa," the spokesperson said.

CNBC has reached out to the other cruise lines for comment.

Of the nine ships, the one getting the most attention is Carnival-owned MS Zaandam which has been at sea for 15 days. So far, four passengers have died while other passengers have displayed flu-like systems. The ship has been denied entry by multiple ports including Cuba, Mexico and Peru. As it makes it way to Florida, Gov. Ron DeSantis has yet to give the ship the green light to dock.

"This has been a complex process with teams of people working day and night to coordinate a safe and orderly return to port for passengers and crew, with cruise lines that must follow greatly enhanced protocols and the requirements of governments and health authorities," said Anne Madison, a spokesperson for trade group Cruise Lines International Association, to CNBC.

Travel experts caution that the longer these ships remain at sea, the more negative attention they will attract.

"It's only contributed to the cruise lines' woes. The sooner cruise lines can get out of the headlines, the better. These ships stranded only extends the pain," said Patrick Scholes, managing director at SunTrust Robinson who covers lodging and leisure, to CNBC.

All of these nine ships were already at sea when the U.S. cruise lines decided to temporarily halt sailings due to the spread of the coronavirus.