Four people are dead after two planes collided mid-air before crashing into a paddock north of Melbourne this morning.

The two planes collided at about 4000ft above sea level, at the popular recreational flying spot of Mangalore, before crashing to the ground.

“Two occupants in each aircraft have died at the scenes,” Victoria Police said in a statement.

All four people, whose bodies were found among the wreckage, are yet to be formally identified.

“One plane almost certainly crashed immediately and the other plane crashed about two kilometres north from here and both were extensively damaged prior to colliding with the ground,” Mitchell local area commander Inspector Peter Koger told reporters.

Victoria Police confirmed that one aircraft was a training flight with both an instructor and a trainee on board.

“It is a big tragedy for both families, I know it is a training flight, it is very upsetting for everyone including emergency services who have attended this scene today,” Inspector Koger said.

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Inspector Koger said there were witnesses to the planes colliding and one of the aircraft coming down.

“There were some people in the paddocks at the back of this facility and there was also a helicopter in the air and we’re working with them to get witness statements,” he said.

Police and paramedics responded to reports of the light plane crash, 120km north of Melbourne, at about 11:30am.

The crash site is about seven kilometres south of Mangalore’s busy airport, where there is a major aviation-training facility and pilot academy.

One of the planes was a Piper-Seminole aircraft operated by flying school Moorabbin Aviation Services that had departed from Moorabbin.

The other was a Beechcraft Travel Air, operated privately out of Tyabb, on the Mornington Peninsula.

Civil Aviation Safety Authority (CASA) spokesman Peter Gibson said they were operating on instruments, meaning the pilots were flying visually and would have lodged flight plans before takeoff.

“We don’t have any explanation of what happened. We can’t speculate on that,” Mr Gibson said.

Channel 9 reporter Tony Jones, who was at the scene, said he could see one of the planes and the damage looked serious.

“It doesn’t look good, I’m afraid,” Mr Jones told Neil Mitchell.

“It has broken up, a number of parts of that plane … have broken free from the actual aircraft.”

The Country Fire Authority confirmed a second plane was found by emergency crews in Avenel, near Seymour.

Australian Transport Safety Bureau inspectors are expected at the scene today to start their inquiry into what went wrong.

All southbound lanes on the Hume Freeway have been closed at Avenel due to the incident.