A security guard has collapsed and died in the cells at Auckland District Court this afternoon after allegedly struggling with a defendant.

Fire crews and ambulances arrived at the court on Albert St at about 1pm today after the medical emergency.

First Security confirmed the staff member had died but deferred to Corrections regarding the circumstances of the incident.

Sources told NZME. News Service the security guard suffered a heart attack while allegedly struggling with a defendant but Corrections would not confirm whether that was the case.

First Security general manager Mike Rutherford said it was a "very very tough" time and out of respect for the employee concerned would not discuss his identity or tenure.

Mr Rutherford said counselling would be available for the man's colleagues and they would do their best to help his family.

"We're a very tight team so we'll offer as much support as we can," he said.

Corrections Northern Regional Commissioner Jeanette Burns also expressed the sympathy of the department.

"We are saddened by the news of the death of a First Security officer today at the Auckland District Court," she said. "We pass our condolences on to the officer's family and friends."

She would not comment on further details about any investigation into the death.

Police were unable to confirm whether anyone would face charges as a result of the incident.