The Health Protection Agency (HPA) said laboratory-confirmed cases of the virus had fallen over the Christmas and New Year period but would pick up over the next few weeks and continue to rise until the end of March.
There have been 4,140 confirmed cases in England and Wales so far this season, 63% higher than the same point last year. But officials say there may be 1.2m unreported cases.
John Harris, an expert in norovirus from the HPA, said: 'Our latest figures covering the New Year period show a further decline in the number of cases and this is what we would expect to see.
He added: 'We can never predict how busy a season will be or what will happen in the weeks ahead although, as with other norovirus seasons, we will expect to see an increase in the number of laboratory reports in the next few weeks until the end of March when activity begins to fall away.'
The HPA has urged infected patients to stay away from GP surgeries, hospitals and care homes to avoid transmitting the illness to vulnerable patients.