From Jayski.com:

Stewart questioned by Australian police UPDATE: #14-Tony Stewart has allegedly been involved in a off-track incident at Sydney Speedway which has seen him interviewed by Parramatta police this morning. Stewart was allegedly involved in a physical altercation with speedway co-owner and former driver Brett Morris after early-evening time trials. It is believed that Stewart, who is racing for a team owned by Morris' business partner and Australian speedway legend Garry Rush, had issues about track conditions after a Hot Lap session and made them known to Morris. A helmet and punches were rumored to be thrown and exchanged during the alleged altercation. Stewart has been competing for the second consecutive year in Australia during his NASCAR "off season". Staff at Parramatta Police Station confirmed to Speedcafe.com.au this morning at 12.49am (AEDST) that Stewart was being held for questioning, but indicated that nothing could be confirmed about the incident until later today including whether Stewart had been officially charged or whether similar charges were being pursued by Stewart against Morris. The final outcome of this situation could result in a raft of ramifications including Stewart's scheduled departure from the country later today, legal requirements back in Australia if it is found he has questions to answer and the overall effect this will have on Australia-US speedway relationships.(SpeedCafe)(1-15-2011)UPDATE: Tony Stewart has walked free after being arrested by local police at the Sydney Raceway last night, but his troubles might not be over just yet. It is understood that Stewart was free to fly back to the US today with fellow US star Donny Schatz, but that further investigations of an alleged assault between Stewart and Sydney Raceway co-owner Brett Morris are on-going. It is believed that Morris, while talked to at the scene of the alleged incident last night, is yet to be formally interviewed. If Morris is interviewed and it is found that Stewart has a case to answer, there is a chance that Stewart may be required to return to Australia for court proceedings. The NSW Police media unit issued the following statement yesterday, which was authorised by area commander, acting Superintendant, Garry Sims."Police from Rosehill local area command were alerted to an altercation involving two men at a car racing track at Wentworth St Granville (Sydney Raceway) about 7.30pm last night. A 39 year-old man was arrested at the scene and was taken to Parramatta Police Station after a 46 year-old man was allegedly struck in the face by a racing helmet. The 39 year-old man was released by police without charge, pending further investigation." Sydney Speedway General Manager, David Lander had little to say about the incident, shrugging off the incident as basically a "tiff" between two drivers. "It is a matter for those two guys (Stewart and Morris)," said Lander. "It was a Ruckus in the pits between two drivers. It happens. There is no more that I can say or I am prepared to say."(SpeedCafe)(1-16-2011)