More than a dozen firefighters attended a fire in a commercial building in north Auckland last night.

The 50m x 100m building on Anvil Rd, in Silverdale, was well alight when Fire and Emergency were alerted at 10.23pm, shift manager Craig Dally said.

But no one was inside the building and the fire at the single-storey building was under control within 45 minutes.

About six fire crews were at the scene last night, he said.