Two custody officers are recovering from facial injuries - after an attack last week at Auckland District Court

The two were escorting a 31-year-old man from the courtroom back to custody - around 3:15 on Tuesday afternoon.

One officer suffered a fractured jaw and the other was knocked out.

Meanwhile, other staff had to rush through several locked gates to restrain the man.

Police believe the attack was unprovoked - but a colleague of the officers says there's been growing agitation in the cells due to overcrowding.

He says many people had been in custody since Friday the previous week - due to delays over the long weekend.