A man is dead after an accident in an Ashburton plastics factory early today.

Emergency services were called to RX Plastics Ltd in suburban Tinwald shortly after 2am.

It was understood the man died after his head became trapped in machinery.

Ashburton police said more information would be available later today.

The Department of Labour has confirmed that it was investigating the workplace-related accident early today.

"This accident is a tragedy and our thoughts are with the victim and their family," the department said.

RX Plastics specialises in manufacturing polyethylene and PVC piping systems, complementing this range with the manufacture of tanks, troughs, fittings, and imported valves and pipe fittings.

It has been operating for more than 30 years and in April last year was sold to the Aliaxis Group, owner of Marley.

No sale price was released, but it was believed to be in the tens of millions of dollars, the Ashburton Guardian reported at the time.

The company has a turnover of around $80 million a year.