Two Melbourne commuters have been given a shock after sitting on sewing needles embedded in a train seat.

Key points: Police are checking CCTV footage as they investigate the incident

Police are checking CCTV footage as they investigate the incident The train has also been inspected by Metro Trains

The train has also been inspected by Metro Trains Anyone with information is urged to contact Crime Stoppers

Anthony Artusa tweeted that he was given a "lovely surprise" after he sat on the seat in which approximately two dozen needles had been inserted.

He said he found them on a city loop train he boarded from West Footscray about 7:45am on Tuesday.

"They were under the surface so [I] didn't see them. Once I sat, they poked out into me," he tweeted.

He said the needles were hidden beneath the material of the seat, and he was uninjured in the encounter.

Metro Trains and Victoria Police's transit division have been scouring CCTV footage to investigate how the needles ended up in the seat, and are aware that another man also sat on the seat.

"Somewhere between 6:00am and 7:00am yesterday morning a further male had got on at Watergardens and sat on that same seat and obviously stood up very quickly and gone to another seat," Inspector Andrew Gustke from Victoria Police said.

"We would ask if that person would come forward to us."

"This is a terrible act of vandalism and we are thankful that no-one was seriously injured," a Metro Trains spokesman said.

Police said needles were not found in other seats.

The train has been pulled from service.

Metro Trains says it was lucky no-one was injured by the needles. ( Twitter: Anthony Artusa )

Last year a contamination scare gripped Australia after sewing needles were discovered in strawberries in Queensland.

The scare sparked copycat cases across the country and growers lost hundreds of thousands of dollars.

A Queensland farm supervisor was later charged with seven counts of contaminating goods.

Police has urged anyone with information about the needles in the train to contact Crime Stoppers.