Dorset Chamber chief executive Ian Girling said: “There will be many people very disappointed by this decision, especially in those areas where there has been a reduction in infection rates.
“Clearly the government is deeply concerned about the risk of rates rising and we have seen that in its messaging about Christmas over the past few days.
“It is absolutely vital that the government does everything it can to support businesses at this time.
“But every individual should also take personal responsibility and follow the guidelines which have been put in place.
“We must do all we can to get through this and move Dorset out of tier two into tier one as soon as possible in the new year.
“Support for all businesses remains available through the Dorset Gateway and we will continue to work with the British Chambers of Commerce (BCC) and ours partners in Dorset to provide the greatest help possible.”