Dudfield Bryce Printers on White St is on fire.
The business is off Marguerita St and fire communication shift manager Craig Dally said crews were called about 3.40pm.
"It's at second alarm so we've got two crews there and three more on the way."
Dally said the building was "well involved".
He said firefighters from Rotorua had been at the fire in the Port of Tauranga earlier in the day, and they had returned by the time this fire broke out.
Iqbal Singh came across the fire while getting food nearby.
"I saw black smoke coming out."
Singh said he had seen what looked like workers evacuate the building which was smoking.
He couldn't see flames and said two fire trucks were at the scene.
A police spokeswoman said police were aware of the fire in a two-storey building and had asked Fire and Emergency New Zealand if it needed police help.
Employees at Advance Steel Engineering next door said they were outside by about 3.45pm.
"It smoked the workshop out and at the same time the printers came out and told us to evacuate."
Within 10 minutes the first fire crews had arrived.
"We asked to knock off early today and were told no, but I guess we got it in the end," one Advance Steel worker said as he watched the blaze.
Another bystander said he was leaving work on Sala St when he saw the smoke.
"I saw it and thought: 'That's a bit thick for the crematorium'."
At 4pm fire crews cordoned off White St when a large crowd of onlookers formed.