A promising NRL star accused of stabbing a man at a church dance party claims he's innocent and was wrongly identified by witnesses because of his high profile.

Manly Sea Eagles hooker Manase Fainu, 21, is behind bars after he handed himself into police on Tuesday in relation to an alleged brawl outside a Mormon church in Sydney's south-west last Friday night.

He was charged with wounding person with intent to cause grievous bodily harm, affray and recklessly cause grievous bodily harm in company

He appeared in Liverpool Local Court, where he was refused bail.

The NRL later announced Fainu has been stood down over the alleged incident, leaving his football career in jeopardy.

With his arm in a sling from a football injury, Manase Fainu was accompanied by his agent when he handed himself into police on Tuesday before being refused bail

Police will allege Fainu stabbed a man, 24, in the back with a 10cm blade at a function held at a Mormon church in Wattle Grove.

The alleged victim was rushed to hospital in a serious condition with a punctured lung.

Fainu's lawyer Elias Tabchouri told the court and reporters afterwards that his client is innocent and will strenuously deny the charges.

Mr Tabchouri told the court Fainu said to him 'there is no way in the world I have stabbed anyone' and that he knew nothing about the stabbing until he was contacted by police, The Daily Telegraph reported.

'He understands he cannot involve himself in any of these antics,' Mr Tabchouri told the court.'

He claimed his client may only have been identified by witnesses because his rising profile in the NRL.

'He has played two years of first grade football so has some notoriety in his community,' Mr Tabchouri said.

'The person (they identified) … is the person they knew, the person who is said to be a first grade footballer.'

Magistrate Joanne Keogh told the lawyer she placed little weight on his argument as she refused Fainu bail.

Fainu will reappear in Liverpool Local Court for a committal hearing via video link on December 16.

Manly Sea Eagles hooker Manase Fainu (right) took his mother to last month's Dally M awards

'We will pursue the avenues available to us to secure his liberty,' Mr Tabchouri told reporters outside court.

'Our client is an innocent man, there's no two ways about it.'

'We respect the decision of the court although we don't necessarily agree with it, but that's fine. We will pursue the avenues available to us to secure his liberty.

'He's obviously very dejected at the moment but again, there are avenues available that we will take and we have to move forward with that.

'He's obviously upset but we'll move forward. He comes from a good family and he'll be fine.'

The NRL's no-fault stand-down rule automatically applies against Fainu because of the seriousness of the alleged offences.

The most serious charge, wounding with intent to or causing grievous bodily harm with intent carries a maximum sentence of up to 25 years jail.

NRL chief executive Todd Greenberg stressed the stand-down rule implemented earlier this year after a horror 2018 off-season makes no presumption of guilt or innocence.

Manase Fainu (pictured) will not be allowed to play for Manly again until the matter is resolved

'The no-fault stand down rule provides for the automatic stand down of players on a no-fault basis where they are charged with a serious criminal offence,' Greenberg said.

'Given the charges, Manase Fainu is automatically subject to the no-fault stand down rule, which will remain in place until the outcome of the court proceedings.'

If Fainu is granted bail in December, he can train with his Manly teammates but is banned from playing at any level until the matter is resolved.

'The club accepts and endorses this decision and will continue to support the well-being of Manase and his family,' the Sea Eagles said in a statement on Tuesday.

Fainu made his NRL debut in 2018 and has since played 34 games for Manly, including two finals matches last month.