Prof Denton said her hospital has three times as many Covid patients than at the height of the first wave in April.
Sickness levels at the hospital are at 13 to 14 per cent, which is "obviously very significant for us", Prof Denton told BBC Radio Norfolk on Friday.
"We've got a lot of staff off sick with Covid-19 or self-isolating because somebody in their family has it and that's put us under even greater pressure".
Covid-19 deaths and cases continue to rise across the country. In Norwich, five people passed away with the disease on Friday, according to hospital’s figures.
Prof Denton said the hospital is working to bring back people who have previously worked in the NHS, and Norfolk County Council has offered support for non-clinical roles.
"I think this is the most challenging the position has ever been for the NHS, and unprecedented times for all of us," she added.
She said the hospital's intensive care unit (ICU) normally cares for around 20 patients, but currently has more than 30 patients there.
Prof Denton said the hospital is treating more than 250 patients who contracted Covid-19 in the past14 days, and a further 70 who have been at the hospital for longer than 14 days.
"We had a short period of time when we've not been able to do as much cancer surgery as we'd like to," she said.
"We're now going to be doing quite a lot of surgery at the (private) Spire Hospital in Norwich and that's going to mean that we will catch up with a backlog of the more urgent things.
"More routine surgery I'm afraid will have to wait until the peak of this pandemic has eased and we have more capacity in the hospital."
She added: "Everybody's under significant pressure."
In London, 200 medical combat technicians will be sent into intensive care units at the city's main trusts including the Royal London Hospital in Whitechapel, east London, and the Royal Free Hospital in Hampstead, north London.
Overall, new cases are falling in the capital but hospitals continue to fill up due to the time-lag between infection and hospitalisation.
Some hospitals are having to transfer patients to ICU's as far away as Newcastle due to a lack of capacity.
Meanwhile, a temporary mortuary with a capacity of up 1,300 was set to open in northwest London on Friday to help local authorities across the capital deal with a surge in Covid-19 deaths.
More than 10,500 people have died in the capital since the disease hit the UK in March.