Emergency crews are battling a fast‑moving fire in Sydney’s south-west, with homes now potentially in its path.

7NEWS.com.au understands firefighters are door‑knocking properties in Leppington, advising residents to prepare to leave as conditions may change.

The blaze is burning through paddocks and pushing west towards Dickson Rd at Leppington, prompting urgent warnings for locals.

According to the NSW Rural Fire Service, the fire has already burnt 16 hectares of land.

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More than a dozen RFS and Fire and Rescue NSW crews are on scene, with seven trucks already deployed and two aircraft racing to assist from the air.

Authorities are urging residents to stay alert and follow instructions as the situation continues to evolve.