A light plane has crash-landed in a small park near a primary school in Sydney shortly before students headed home for the day.

The Piper PA-28 took off from Bankstown Airport, in Sydney’s southwest, about 2.20pm on Thursday before crashing into trees next to sporting fields at nearby Bossley Park about five minutes later.

A 37-year-old man and a 34-year-old woman were onboard but sustained only minor injuries.

A NSW Ambulance spokesman said the pair did not need to go to hospital and refused further treatment from paramedics.

The plane was on a training flight and appeared to suffer engine failure before making the emergency landing, Fire and Rescue NSW said in a statement.

The plane was believed to be carrying up to 340 litres of fuel and a 100m fire protection zone was set up to monitor for leaks, it said.

The park where the plane came down neighbours Mary Immaculate Catholic Primary School and its principal, Beverly Coffey, said parents coming to pick up their children informed staff of the crash.

“We thought they might have had too many drinks in the afternoon, but then we looked out and we could see it,” she said.

Teachers and administrative staff donned high-visibility clothing to handle “some pretty upset kids”, but the crash did not otherwise impact the end of the school day, Coffey said.

It appeared the plane may have used trees in the park to soften its landing, she said.

The Australian Transport Safety Bureau is investigating the incident.

Two people sustained minor injuries when the plane they were in crashed in Sydney's southwest. – AAP