Pedestrians are reflected in an electronic board outside a securities firm in Tokyo, Japan.

Asian stocks declined on the final trading day of the week, as investors awaited the U.S. nonfarm payrolls report for August that may play a crucial role in the Federal Reserve's decision about when to lift interest rates.

A strong jobs number could allay fears over global growth, but it could rekindle speculation of an interest rate hike in the U.S. as soon as this month, which could hurt risk assets, particularly in emerging markets.