Ottawa police Const. Shyldon Safruk arrives in court Monday morning. (Steve Fischer/CBC)

An Ottawa taxi driver is denying he took a swing at a police officer who he accuses of using a racial slur and breaking his wrist and finger.

Sami Aldoboni was the second of two witnesses to testify on the first day of the assault trial of Ottawa police Const. Shyldon Safruk.

Safruk, 36, is accused of attacking Aldoboni, 44, while the officer was off-duty in the parking lot of the airport.

Aldoboni told the court Monday he was heading to the Ottawa International Airport along the Airport Parkway on the afternoon of May 11, 2009, when he noticed a dark-coloured SUV trying to merge from Brookfield Road.

Aldoboni said that Safruk, who drove the SUV, tailgated him and attempted to pass him, nearly causing an accident. Aldoboni also testified that Safruk gave him the finger.

Safruk followed him into the taxi staging area at the airport parking lot where drivers line up to wait for fares, Aldoboni said.

He testified that Safruk got out of his SUV and shoved him hard, and shouted a racial slur. He also said Safruk grabbed his jacket, wrestled him to the ground and twisted his left arm behind his back, breaking his wrist and finger in the process.

But Aldoboni refuted the testimony of a witness who said he saw Aldoboni try to punch Safruk.

That witness, taxi driver Yousef Matar, testified he saw Safruk and Aldoboni fighting. He said that at one point, he saw Aldoboni on the ground with Safruk standing over him, saying, "Come on up if you want to try again."

Earlier Monday, Safruk pleaded not guilty to assault causing bodily harm.

Crown prosecutor Ian Bulmer also screened 32 minutes of surveillance footage of the parking lot from around the time of the scuffle.

The security camera was positioned several hundred metres away from where it occurred, so it was "very difficult to make out anything but taxis and then police cars coming and going," said the CBC's Alistair Steele from the courthouse.

"At one point there does appear to be some kind of commotion but it was impossible, at least from our vantage point in the courtroom, to see who's involved."

The trial continues Tuesday and is expected to last all week.