Sydney Roosters forward Spencer Leniu has apologised to Brisbane Broncos five-eighth Ezra Mam for making a racist remark during last Sunday's NRL match in Las Vegas.

The Roosters released a statement on Thursday, saying Leniu will enter a guilty plea to a contrary conduct charge.

"I want to apologise to Ezra and his family for using the word I did and I am sincerely sorry to cause him such distress," Leniu said.

Leniu added: "I've put my hand up and want to take ownership of this. I said the word but I didn't mean it in a racist way. Anyone who knows me knows that's not who I am."

Leniu has been referred straight to the NRL judiciary.

Roosters chief executive Joe Kelly said the club did not "tolerate any form of racism".

"We extend our deepest apologies to Ezra, his family and the wider Aboriginal and Torres Strait Islander community and offer our support to all parties during this time," Kelly said.

"We respect the judiciary process. Accordingly, the club will not be making any further comment prior to the hearing."

The Broncos acknowledged Leniu's apology via a statement released on Thursday.

"There is no place for racism in our game or in our society," the statement read.

"The club respects the NRL Judiciary process that is still to play out and we will make no further comment on that.

"Ezra's wellbeing has been our primary concern from the start.

"He has been well-supported within our club and we will continue to focus on that in the time ahead."

Leniu will face the judiciary on Monday night and is expected to be hit with a lengthy suspension.

He was placed on report in the 69th minute of the Roosters' 20-10 win over the Broncos after Mam – who is Indigenous — made a complaint to referee Adam Gee.

Leniu had initially dismissed the incident as "nothing" and said he was "not worried at all".

"It's all fun and games on the field," he told Triple M while still on the field.

After the match, players from the two clubs exchanged words as they passed each other at the hotel where they were both staying.

Witnesses said there was no threat of a physical altercation, and Leniu was ushered down the corridor by club staff as words were exchanged.

The teams were sharing the same floor at the hotel.

In the wake of the incident, Broncos teammates Reece Walsh, Kotoni Staggs and captain Adam Reynolds all came out in support of Mam.

South Sydney's Indigenous All Stars Latrell Mitchell and Cody Walker also backed Mam on social media.