Second fire at Melbourne recycling plant

A huge blaze is burning out of control at a recycling plant in Melbourne's north as more than 70 firefighters work to put out the second fire there in a year.

The Metropolitan Fire Brigade arrived at SKM Recycling in Maffra Street, Coolaroo just after 7.30pm on Saturday and began tackling a fire in a large shed containing bales of co-mingled recycled material.

Police, paramedics and the Country Fire Authority are also on scene.

There are no reports of any injuries and the cause of the fire is unknown.

A worker from aged care home Estia Health, close to the plant, has told AAP there is a faint smell of smoke outside but she cannot see flames.

Nearby residents have been warned to monitor conditions.

"If you are sensitive to smoke or you live with someone who is sensitive to smoke you should close windows and doors. Turn off heating and cooling systems," the Vic Emergency website reads.

The SKM Recycling plant last caught fire on July 13, 2017 and burned for 11 days.

The plant's owner became the subject of a class action law suit by 180 residents forced to leave their homes.

They claimed the company was negligent because it knew there was a fire risk and should have done more to protect the nearby Coolaroo and Dallas neighbourhoods.

A number of people were hospitalised and had ongoing health concerns months afterwards.

Late last year a Victorian government report found the state's dumps were ill-equipped to prevent fires.