Man on 19 charges from Brisbane siege

A disgruntled ex-employee who threatened former workmates in a 10-hour siege at a food processing plant in Brisbane's west will face 19 charges in court on Friday.

The 46-year-old man had armed himself with a large knife but was finally detained and arrested after specialist police entered the building on Thursday morning.

He armed himself with a large knife, threatened staff and engaged in a scuffle before reportedly barricading himself inside an air-conditioning shaft at the Wacol plant around 10pm on Wednesday.

No one was injured in the scuffle.

Police say the man complied with directions when specialist police found him in the building around 8.30am on Thursday.

"He was located in the building here and complied with police directions and came with them peacefully," Acting Inspector Janelle Andrews said.

She said the size of the plant posed a significant challenge to police.

"Obviously we've got a very large building here, (the) size of two football fields, to clear and to locate the person not knowing what the situation was."

The man was charged late on Thursday with a variety of offences including six counts of common assault, four of making threats and assault occasioning bodily harm.

He is due to appear in the Richlands Magistrates Court on Friday morning.