Bystanders tried to resuscitate a driver who suffered a medical event and crashed his vehicle during a fatal Hastings incident, a witness says.

The incident happened about 4.55pm on Tuesday near the intersection of Frederick St West and Tomoana Rd in Mahora, which is surrounded by a cluster of shops.

Police confirmed one person was found deceased following a single-vehicle crash.

Hastings resident Courtney Leonard-Wheeler was driving close by and saw another car - a green Toyota - make a turn through the traffic lights, then slowly veer across the road.

Leonard-Wheeler pulled over and went to check on the male driver, alongside other concerned motorists and bystanders.

Bystanders managed to get his door open and put him in the recovery position outside, and started to perform CPR.

Emergency services arrived soon after and paramedics unsuccessfully tried to resuscitate him.

Police said the matter had been referred to the coroner.

Earlier this week, investigators were seeking information from witnesses who had seen the small green Toyota hatchback in the lead-up to the crash, and encouraged people with information to call 105 and reference event number P055371468.