Warriors captain Addin Fonua-Blake has reportedly been warned, along with three Manly players, over allegedly using their platform in the sport to pay homage to jailed friends.

Three of the Manly players who refused to wear a rainbow-coloured jersey on religious grounds showed their support for a convicted criminal during Sunday's NRL match against the Gold Coast Titans.

Gun youngsters Haumole Olakau'atu and Josh Schuster, along with prop Josh Aloiai, made public displays of support for their former teammate Manase Fainu as he prepared to go to jail for stabbing a Mormon church leader.

Oloakau'atu flashed the "2161" postcode for Guildford where the pair grew up playing footy during a try celebration, while Schuster scribbled the initials MF on his wrist and shared a tribute to his "toko" on Instagram.

Fonua-Blake, who played with Fainu at Manly, also appeared to pay tribute to the troubled hooker as he celebrated a late try during Friday's upset win against the Bulldogs.

Fonua-Blake's partner, Ana, also posted a message of support for Fainu and his family on Instagram, saying "always be beside you through it all".

Addin Fonua-Blake's celebration after his try against the Bulldogs. Photo / Sky

According to The Daily Telegraph, NRL integrity boss Jason King reached out to Manly chief executive Tony Mestrov and Warriors counterpart Cameron George on Wednesday, urging them to speak to their players about the need to respect the game's image.

"This is something that our integrity team is taking a look at," NRL chief executive Andrew Abdo said, according to the News Corp publication.

"We are in active dialogue with the clubs involved. I am not necessarily pleased with the fact we have allegations of players showing support potentially under these circumstances.

"But we will need to look at it. We are in dialogue with the club and I think the club will deal with the matter with the players.

"I think it is important for us to understand the context of what has happened.

"I am not in position to pass judgment because I am not sure what the context is for this. That is happening now through discussion with the club.

"Once we know that then I think we will deal with it. I am not saying there has been any breach of the rules but clearly we want to make sure that this isn't something that is seen as s negative for our game, for the players and for the sport more generally."

Haumole Olakau'atu's celebration in support of former teammate Manase Fainu. Photo / Sky

For many Sea Eagles fans, the decision to show solidarity with Fainu appeared directly at odds with their controversial choice to stand themselves down for a must-win clash against the Sydney Roosters two weeks earlier due to the pride jersey.

The trio, along with teammates Jason Saab, Christian Tuipulotu and Toafofoa Sipley, were dubbed the "Manly 7" after refusing to play in protest of the pride jerseys.

Waves of disappointed Manly supporters took to social media to declare they could no longer support the club, accusing the trio of double standards.

"They're using the NRL and Fox as a stage to show their support. That's where it's wrong, that's where the game has to be tough," News Corp journalist Paul Crawley told Fox League's NRL 360 on Tuesday.

"There's concern that at some clubs there is gang culture and Manly is one of them and you have to stamp it out, that's where the game has to be tough."

Aloiai supported Fainu throughout his trial and posted a photo of the pair smiling together outside of court after the 24-year-old hooker was found guilty by a jury of the violent attack outside the Sydney church in 2019.

A jury took just two hours to find Fainu guilty of plunging a steak knife into the back of Faamanu Levi at the Church of Jesus Christ of Latter-day Saints at Wattle Grove in October, 2019.

Following the verdict last week, Crown prosecutor Emma Curran made an immediate detention application, however it was not able to be heard by District Court Judge Nanette Williams until Monday.

Manase Fainu arrives at Parramatta Court. Photo / John Grainger/news.com.au

Fainu's barrister, Margaret Cunneen SC, on Monday morning fought the move for him to be immediately sent to jail while he awaits sentencing, arguing he needed time to prepare financially and mentally.

Under the state's new bail laws, a defendant who is facing inevitable full-time imprisonment must demonstrate "special or exceptional circumstances" to remain on bail while they await sentencing.

And Judge Williams said she was not satisfied that had been demonstrated by Fainu.

Fainu, wearing a grey suit and blue and white tie, was placed in handcuffs by sheriffs, hugged Ms Cunneen and waved to family members as he was led away.

But his solicitor Paul McGirr said the "wheels are in motion" in preparing an appeal.

Outside court, Mr McGirr described the verdict as "dangerous".

Throughout the trial, Fainu had argued it was a case of mistaken identity.

His legal team had said that key witnesses were swayed after they were shown social media pictures of the Tongan international in a sling in the hours following the incident.

Mr McGirr told NCA NewsWire that Fainu would not launch his appeal until after he was sentenced later in the year, but that he would challenge the verdict in the Court of Criminal Appeal.

"The judge's directions were very fair, especially in regards to scrutinising identification," Mr McGirr said.

He also said they believed the case involved a number of people all talking, not knowing who was who and looking up Facebook and Instagram and everything else.

"And to me, that's very dangerous ground – when people are telling other people who's who."