Purecraft Bar & Kitchen, located in the city center, said that it was experiencing cancellations of up to 30%.
The Colmore Building is a block of offices that can accommodate 3,000 people. The current number of employees at The Colmore Building caterers is 800.
According to the government, people in England should return to work if possible, as part of its efforts to combat the Omicron variant.
If approved by MPs, some venues and events may be required to verify the Covid status for visitors over 18 years old from Wednesday.
Paul Brazier from Purecraft said that the company was dependent on people who work in the business district.
He said, "It's going to impact us significantly, people working at home. It's something we've already seen when the government made these decisions before and it's something we'll see again.
"It's severely impacting our business, and we're seeing as high as 30% cancellations of our bookeds now."
The Colmore Building's Caterer Lee Thomas said that "Throughout lockdown, we've been in and outside kind of three to four times and we have rebuilt it again. So as of January, we'll begin again and do it again. Rockfine Group Ltd's Michelle Dalton is the head of a company that provides management consulting services to businesses looking for new revenue streams.
She said that the government was giving them the freedom to make the best decisions for our team as well as our business. The company will have a work from home arrangement starting Tuesday.
Ms Dalton said while home working reduces virus transmission "we also have to balance that with the wellbeing of our employees... and then the needs of the business to have team working together, sharing ideas effectively".Rockfine Group project executive Georgia Greenburgh is prepared to do what it takes to avoid another a lockdown.
She stated that she hoped to have some social interaction this time, not like being locked in your home again.
"It's important to understand why we have [to do it]. It's frustrating, more than anything. It's like stopping and starting at the beginning of what was meant to be an exciting time in your life.