An Auckland Catholic boys' school has closed for the day after threats were made against people connected with the college.

Sacred Heart College has told pupils to not come to class today.

Police are investigating the incident with the area commander saying they were "treating the matter seriously".

A text and an email sent to parents says the threat was made through social media.

It was directed at two people connected to the school.

"The police have advised that, given the nature of the anonymous threat, we err on the side of caution and close the school for the day until their investigations are completed," the email read.

A college spokeswoman said boys had been asked to stay home or, if they had already arrived at school, to return home.

The college was now working with police to investigate the source of the anonymous threats.

A statement on the situation was expected to be made to the school community when more was known, she said.

Area Commander Auckland East Inspector Jim Wilson said police were aware of a threat sent to an east Auckland school.

"We are treating the matter seriously and are liaising with the school," said Wilson.

"Locals will notice an ongoing police presence in response to this incident."

He said the school had decided to close for the day out of precaution.