A Sydney man has pleaded guilty to impersonating a Chinese police officer on the streets of Strathfield in a bizarre case that has left authorities baffled.

Kunlang Lie was arrested after officers discovered his black Mercedes bearing fake Chinese police insignia this time last year.

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A search of the vehicle uncovered 48 rounds of ammunition hidden in the boot.

The 21-year-old has now entered a guilty plea to the charges.

A judge has ordered Lie to see a psychiatrist before he is sentenced next month.

The case has raised questions about the man’s motivations for impersonating a foreign police officer on Australian streets.