Teen pop star Justin Bieber has had assault charges against him dropped.

The 20-year-old was charged in January in connection with an alleged assault on a limo driver in Toronto last December.

According to the driver, who picked up Bieber and six members of his entourage from a nightclub, one of the passengers – allegedly the pop star – struck him on the back of the head several times.

However, prosecutor David Mitchell said on Monday that the case would be withdrawn due to lack of evidence.

"There were a number of people in the vehicle seated behind the driver at the time of the incident and the Crown is not in a position to establish the identity of the person who came into contact with the complainant beyond a reasonable doubt based on the available evidence," Mitchell said.

The teen is still facing separate charges of dangerous driving and assault, however.

Bieber is expected to appear in court on September 29 in relation to an incident in his hometown of Stratford, Ontario in August.

He was arrested after apparently becoming engaged in a "physical altercation" with the driver of a minivan into which he had crashed a quad bike.

The 'Beauty and a Beat' singer is also currently on probation in Los Angeles after accepting a plea deal for throwing eggs at a neighbour's house causing thousands of dollars of damage.

Despite his reputation, Bieber enjoys a close relationship with Hillsong NYC pastor Carl Lentz, as well as lead pastor of Seattle's The City Church, Judah Smith, who apparently texts the pop star Bible verses each day.

Bieber was even baptised in a bathtub by Lentz in June, and is regularly reported to attend Bible studies, often with on-off girlfriend Selena Gomez.

Lentz told CBN in March that the pop star is "a good kid. He's trying to figure this out".

"People who are like, 'Is he even a Christian?' With Justin, I tell people grace and acceptance does not mean approval. I can accept you as a human being and not approve of your actions. That's how we've been loved. We love because we were first loved," he said.