Guests at a quarantine hotel, which a council has requested to be closed, have criticised conditions there.
Reading Borough Council has called for the "urgent" closure of Penta Hotel in Oxford Road after it said it had been linked to a "significant" number of positive cases.
Some guests have said there is a lack of ventilation at the facility.
The Department for Health and Social Care (DHSC) described it as a "small localised outbreak".
Penta Hotel said in a statement: "To this date, the facility continues to closely adhere to all of security guidelines and policies set out by the government department."
There has been a total of 44 positive cases of Covid-19 among residents and staff at the DHSC-run quarantine hotel, which opened on 29 April.
The majority of cases have been identified as the Delta variant, first identified in India, by Public Health England (PHE).
Reading Borough Council said it believed at least three cases in the community had been directly linked to the hotel's outbreak.
It added it had "no confidence" in safety measures at the hotel and felt it needed to be shut.
Raz, from Harlow, Essex, who did not want to give his surname, said he had paid more than £1,750 to stay at the facility, having travelled back to the UK from Pakistan, which is on the red list.
"I survived my trip, I survived my flight, and I'm struggling right now," he said.
"I'm not sure I'm going to survive this quarantine facility.
"This is not a facility to protect yourself from the virus. This is a facility to give you a new variant."
He added the room was hot and had poor ventilation.
Saedeep Sharma, from Swindon, Wiltshire, has travelled back from India, which is also on the red list.
He said his wife had tested positive for coronavirus on day eight of their stay at the hotel, and they had to stay for another ten days.
He claimed it was likely guests would catch the virus as staff were bringing fresh bedding and towels to rooms.
However, he said he did not think things could be done differently.
DHSC said it had issued "clear public health guidance" to quarantine hotels, including strict infection controls and training hotel staff to minimise the risk of outbreaks.
"There was a small localised outbreak at this managed quarantine facility, which was identified by our enhanced testing regime," a spokeswoman said.
"Local public health teams have finished investigating and all individuals who have had a positive test result have been instructed to quarantine for 10 days from the day of the test."
She added DHSC continued to work with PHE and local officials.
Dr Mattea Clarke, consultant in health protection at PHE South East, said: "All cases and their close contacts have been instructed to self-isolate in line with national guidance, to avoid spreading the virus."
She added: "Staff have been advised to isolate and book a test if they are symptomatic, in addition to participating in the daily rapid testing in place for all hotel staff...
"Since the initial phase of the outbreak in early May we have seen a small number of further cases among staff but the evidence shows the outbreak has slowed and that the control measures have been effective."
Penta Hotel added it was not in a position to comment on the topics raised by Reading Borough Council.
Four areas in Reading, including the area where the hotel is, are part of a surge testing operation.