A grocery run turned into a snake rescue for an Australian woman when she was greeted by a python poking out from a supermarket shelf.

Helaina Alati, 25, was at a Sydney store on Monday when the 3m non-venomous snake slithered out.

The Woolworths supermarket lies on the edge of a large expanse of bushland on the city's north- west outskirts.

But encountering a snake in the spice aisle is not what Ms Alati expected.

Fortunately for both parties, Ms Alati is a wildlife rescuer and familiar with snakes.

"I just turned my head and he was about 20cm from my face, just looking straight at me," she told the BBC.

She did a double-take but remained calm. No one else was around.

Recognising it instantly as a diamond python, Ms Alati knew it wasn't venomous as it protruded and flicked its tongue.

"He was looking straight at me the whole time, almost like he was saying: 'Can you take me outside please?'" she said.