A person is dead and a man is in custody after multiple people were stabbed in broad daylight near a busy Sydney train station.

Police responded to reports of the stabbing in Merrylands, in Sydney’s west, about 10am on Tuesday.

They were told a man had fled on foot after stabbing multiple people.

Paramedics treated three victims at the scene.

One was declared dead, with the other two victims transported to Westmead Hospital in a critical condition.

Police are yet to formally identify the man who died. However, they said he was aged between 30 and 40.

A man, 22, and woman, 47, were critically injured.

Shortly before 11am, police confirmed a man had been arrested and taken to the nearby Granville Police Station.

The man was arrested on Smythe Street in Merrylands.

Superintendent Simon Glasser said later that the suspect was known to police.

“The male has a history for low-level crime but most of his history with us is mental health-related,” he said.

The man was not linked to the victims and it appeared as though the “highly confronting” attack was random.

Police had retrieved a weapon, similar to a 20-30-centimetre kitchen knife, although it was not certain if it was the weapon involved in the stabbing, Glasser said.

“As far as we’re aware, at this point there is no relationship between the three victims.

“They were by themselves on Merrylands Road when this has occurred.”

The stabbing took place during a busy time on the street. Photo: Nine News

Glasser said it was a “horrible offence to have taken place” just before lunch when there were many people around.

“It would obviously be very confronting for anyone that was in the area at the time.

“However, we have arrested an alleged offender for this offence.”

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.

-with AAP