Issac Luke and Sonny Bill Williams were guests at the birthday party of one of the double international's nieces in Sydney yesterday though the former Kiwis teammates and NRL rivals were not entirely in a mood to celebrate.

For Williams, his second stint in the NRL ended with a preliminary final defeat to Luke's South Sydney Rabbitohs on Friday night - the exceptional hooker also had the euphoria associated with his team progressing to the grand final for the first time since 1971 tempered by the realisation he may banned from taking part.

Luke was placed on report for a lifting tackle on Williams in the 38th minute of the Rabbitohs' 32-22 victory at ANZ Stadium, and although the second rower turned All Blacks' second five-eighth was able to play on, the incident is likely to have drastic repercussions for one of the NRL's leading dummy halves.

There was no animosity at the family gathering - Luke's wife Mickayela is a cousin of Williams - and he said it would be a "travesty" if his close friend was suspended from the pinnacle of a first grade career that started at Souths in 2007.

Luke and Ben Te'o combined to hoist Williams, though it was the nuggety Kiwi who drew the penalty - and the punishment could be even more severe tomorrow when the NRL's match review committee confirms its charges tomorrow.

His latest indiscretion does not compare with his aim to break the leg of his cousin and England international Rangi Chase during the 2011 Four Nations tournament.

But because he already pleaded guilty to a dangerous contact charge when tackling Steve Matai in August, Luke has carry over points that will see him ruled out of the decider if he is slugged with even a grade one dangerous throw.

If that scenario unfolds he will have to successfully fight the charge before the judiciary on Tuesday - where Roosters props Jared Waerea-Hargreaves and Sam Moa may also have their post-season wind-ups disrupted.

Waerea-Hargreaves was placed on report for apparently head butting Ben Te'o while Moa risks missing next month's Four Nations opener against the Kangaroos after a swinging arm connected with Kirisome Auva'a.

Luke looked resigned as he retreated to the defensive line after checking on Williams' welfare  but tried to stay positive after a comforting reunion with Mickayela and their two children in an otherwise buoyant annex inside the stadium.

"We'll have to think about it, obviously we'll go through it whenever we get charged. All I'm worried about now is our win and our recovery," he said, reluctant to comment further.

A member of the teams that lost the last two preliminary finals to the Bulldogs and Manly, Luke played a significant role in the 32-22 victory with 11 typically sniping runs from the play-the-ball making 106-metres.

If suspended, his loss will be a major setback for the Rabbitohs, although Penrith-bound Apisai Koroisau was an effective deputy when Luke was sidelined with a shoulder injury in March.

Interchange forward Jason Clark can also fill in at hooker though he does not have the dynamic qualities of the 29-test international.

Although he did not want to dwell on the tackle, Luke was happy to acknowledge the significance of the Rabbitohs' triumph on a personal and collective level.

"To be able to represent the players from the past in a big match is a real honour. I'm humbled by it," he said. 

"There's a great history behind us so to have a chance to be on the same charts as the legends of the club is great," he said, noting: "We haven't really done anything (yet)."

No doubt Luke will be hoping the match review committee take a similar view on his technique to stop Williams.

- Stuff