Guests 'fled a hotel' as an investigation was launched into diarrhoea and vomiting cases.
Council chiefs are probing cases of viral gastroenteritis at the Hydro Hotel in Wales the authority has confirmed.
Some guests left early and opted return home after they became ill.
There were also claims "around 30 people had checked out" early from the Llandudno hotel as they feared the would become ill.
NorthWalesLive reports that a guest, who wished to remain anonymous, said: "We arrived at the Hydro Hotel on Monday morning.
"The next day I began to suffer from diarrhoea and nausea which I put down as food poisoning.
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"After speaking to other guests the following day and today, I found that quite a few people had been suffering from the same symptoms and that around 30 people had checked out from the hotel as a result.
"We were given letters telling us what to do should we fall ill when we first checked in and, when we went to the reception to ask what was going on, they told us there was a virus going around Llandudno.
"One of the other guests told me they had to call a doctor at the start of the week because they were so unwell.
"Guests at other hotels seemed fine so I wasn't sure about that and because we travelled here by car, we decided to cut our stay short and travel back to England today.
"It's lucky we didn't come here in a coach like a lot of other people, otherwise we'd be stuck there."
Graham Brown, consultant in communicable disease control for Public Health Wales, said: “Public Health Wales have been made aware that Conwy County Borough Council is currently investigating a number of cases of diarrhoea and/or vomiting linked to the Hydro Hotel in Llandudno.
“We would remind anyone who is unwell at any time with diarrhoea or vomiting that they should seek advice from NHS Direct Wales or their GP if they are concerned about their symptoms.
“It is also important to avoid spreading infection to other people at home, and people who are unwell should wash their hands thoroughly with soap and warm water after using the toilet and before preparing food, and should not share towels with other people.”
A response from the Regulatory Services via Conwy Council read: "Environmental Health Officers are aware of ongoing cases of viral gastroenteritis at the hotel and liaising with the hotel management team."
In recent days, a number of residents at the Hydro Hotel have shown symptoms consistent with norovirus.
A spokesman for Alfa Travel, which runs the hotel said: "In line with our health and safety procedures, we have been in regular contact with the local environmental health department and followed all guidance.
"As a precaution, we have decided to close the hotel for a short period this weekend to allow a further deep clean to be carried out to ensure that the virus is contained before reopening on Sunday evening."
