King's Lynn Stars' play-off hopes could receive a mammoth blow if they are found guilty of illegally using Kozza Smith against Peterborough Panthers.

The Australian, who guested for Lynn in their 47-43 win on July 24, is at the centre of an eligibility row after coming into the side as a replacement for Nicklas Porsing.

A Speedway Control Bureau spokesman confirmed they were looking into the fact that Smith's converted average was too high for the man he was racing instead of. While Porsing rides on an average of four, the Aussie's converted Premier League one – thought to take precedent over his Elite League average of 3.43 – is 4.45.

Lynn chiefs maintain the wording of the rule on reserve guests is down to interpretation and insist they were given permission to use Smith by SCB referee Dave Watters on the night.

If punished, the former full-time Lynn rider's 13 points would be scrubbed out. It would turn the Stars' victory into a 43-34 loss and Rob Lyon's men would be docked two points. They would then sit seven adrift of the top four with just eight meetings to go.

Lyon said he would not be making any comment on the matter while he remained 'in consultation' with the SCB. But previous incidents suggest he could be wasting his time.

Last season, Poole were docked a point for illegally using guest Ty Proctor in a win at Peterborough.

A decision is expected to be made before the weekend.