Police who chased a man before he jumped into the Parramatta River and drowned say he may have been linked to a suspicious luxury car found minutes earlier.

Officers on patrol located an abandoned white BMW about 3.45am on Thursday in Nordica Street, Ermington, in Sydney's west.

Their suspicions about the vehicle led them to pull over a taxi about 30 minutes later in the same street.

Police approached the cab and began making inquiries when a woman and a 31-year-old man ran from the vehicle.

The woman was stopped a short distance away, but the man led officers on a foot pursuit for up to 100 metres to the bank of Parramatta River. By the time police reached the river's edge, they had lost sight of him.

The man's body was recovered from the river about 5am some 1.5 kilometres downstream from where he was believed to have entered the water. AAP