The virus-hit cruise liner Aurora arrived back at its home port of Southampton today, with angry passengers threatening legal action over their ruined holiday.

The £200m ship was at the centre of a diplomatic incident with Spain and its passengers were earlier banned from landing in Greece because of a stomach bug, known as norovirus, which struck down 500 of its 1,800 passengers.

The ship docked at Southampton's Mayflower Cruise Terminal at 6am, and passengers disembarked to tell of their bouts with the highly infectious norovirus. The stomach bug, which causes vomiting and diarrhoea, prompted Greece and Spain to take action to prevent Aurora passengers landing on their shores.

Passenger Tricia Campbell, 55, of Hatfield near Doncaster, said she was considering legal action against P&O after she caught the virus. She said as soon as they arrived on board the Aurora there were notices put up in their cabins warning about the norovirus.

"I suffered from dehydration because of the vomiting and diarrhoea which led to me getting a kidney infection which I've been on antibiotics for. I had terrible pains," Ms Campbell said.

"Immediately after getting on board, we suspected there was going to be a problem because of the notices delivered to our cabin and then people started going down like flies. Then we were avoiding people, avoiding places, until you inevitably went down with it.

"I went on the holiday by myself and I thought I would make friends but I hardly met anyone because I had to stay in my cabin for much of the time," she added.

Passenger Michelle Seaborn agreed that the virus was already on board when the flagship liner left Southampton on October 20 for a European cruise. Both she and her husband Barry fell ill.

"It was on board when we got there and it's their fault that we got it. They put a notice up warning passengers and that but it's not good enough. P&O (cruises) are at fault. They knew all about it and they should have cancelled the voyage and given us our money back," Ms Seaborn said.

Ms Seaborn added that she would be suing for kidnap after P&O refused the couple permission to leave the ship at Gibraltar and fly home.

P&O countered that the Gibraltar government would not allow passengers to disembark.

"Passengers did not have medical clearance to leave Gibraltar. And the Gibraltarian government imposed strict conditions for the (port of) call to take place," the company said in a statement.

After the Aurora was refused permission to dock at Piraeus in Greece, the ship sailed for Gibraltar. Spain closed the border with the Rock for the first time in 18 years after the ship docked on Monday, fearing the bug might cross into the country. The foreign secretary, Jack Straw, called the move "unnecessary and disproportionate".

Passengers well enough to go ashore had to hand in their passports so they could not cross into Spain and the border remained closed until the liner left.

Yesterday P&O Cruises said two men in their 70s had died during the trip but that their deaths were not related to the bug.

Some passengers claim staff sprayed the ship with chemicals to contain the virus and passengers with the virus were confined to their rooms.

Health officials were meeting Aurora representatives to talk about the virus and standard health procedures. A P&O Cruises spokeswoman said only one passenger was still showing signs of the illness.

Not all passengers disembarked threatening legal action, however. Helena and Andy Banks, both 42, who were on the cruise with their children Lewis, 8, and Matthew, 6, said they all contracted the virus.

"It wasn't P&O's fault," Mrs Banks said today. "We were poorly and not feeling well. We did not want to leave our cabin because when you're feeling ill, you do not want to go running about.

"We slept it off, and it was literally for 24 hours. The crew dealt with it extremely well and we are not going to look for any compensation," she said.

David Roderick from Lytham St Annes, Lancashire, went down with the virus twice, but said: "I will not be suing anybody because I believe the crew did everything they could, and I am taking the view that it's one of those things."

A spokeswoman for P&O explained that the boat would now be thoroughly cleaned before passengers embark today for an evening sailing on a three-day cruise around the Channel Islands and back to Southampton.

The managing director of P&O Cruises, David Dingle, said the company would look very carefully and give very careful consideration to claims from passengers for compensation when they start to arrive.

"We need to be fair to everybody about this situation and I would like to think our passengers themselves will take a fair view," he said.