A number of people were injured in a stabbing at a church in a suburb of Sydney on Monday, police said.

Officers arrested a male and he is assisting police with inquiries, a police spokesperson told Reuters, following the attack in Wakeley, about 30 km (18 miles) west of the central business district.

It was the second reported mass stabbing in just three days in Sydney after six people were killed in a knife attack at a mall in the Bondi area.

Monday's attack happened during a service at Christ The Good Shepherd Church in Wakeley, and police were still at the scene trying to control large crowds gathered for the event.

The injured people suffered non-life-threatening injuries and were being treated by paramedics, police said.

Local media reported that a church leader and several worshippers were stabbed during a service at the church. Videos of the incident circulating online showed a man lunging and stabbing a speaker.

The New South Wales ambulance service said at least four people were injured including a man in his 50s who was taken to hospital in a serious condition. There are 11 ambulances on the scene.