In a severe blow for Tunisia's tourist industry, Spain's MSC Cruises and Italy's Costa Crociere said none of their boats would berth in the north African country's capital until further notice.
The boats whose passengers were caught up in the attacks both left Tunis on Thursday for the next scheduled stops on their cruises.
Costa Crociere said in a statement on Thursday that four Italian passengers and one Russian on the Fascinosa liner, which was docked at Tunis port at the time of the attack on Wednesday, were among at least 20 foreign tourists killed.
Another seven Italian passengers and one Russian were injured, the company said.
Nine passengers on the MSC ship died including three Japanese, two Colombians, two Spaniards and two French nationals.
A further 12 passengers were injured and six had not returned to the MSC Splendida when it left Tunis on Thursday morning, bound for Barcelona.
Three passengers on the Costa Fascinosa died, the company's CEO Michael Thamm said in a statement. Eight others were injured and two were unaccounted for. The nationalities of the deceased were not released.
The ship set off from Tunis in the early hours for the Spanish island of Mallorca.
Costa said the suspension would affect three of its giant ships which had been due to berth in Tunis in the coming months - the Costa Fortuna, Costa Favolosa and the Costa neoRiviera.
MSC also had three boats scheduled to dock in Tunis in the near future.
In a statement, Costa said: "The safety of our guests and crew is Costa Crociere's priority and an essential requirement for providing peaceful and relaxing holidays.
"After what happened in Tunis, we have decided to cancel all upcoming stops by our boats."
Both companies said they were working on alternative ports of call for the affected cruises.
Costa said two of its executives and 12 other employees were in Tunis helping the injured and attempting to track down the two missing passengers.
Both ships had more than 3,000 passengers on board when they arrived in Tunis.