Roger Henry Lavin, 70, pleaded not guilty in the Launceston Magistrates Court today to having driven without due care and attention.

During the hearing, police prosecutor Konrad Plachta called four witnesses, including Cycling Tasmania executive officer Collin Burns.

Mr Burns told the court he was part of a bunch of about 14 cyclists riding along the West Tamar Highway at Legana towards Launceston before 9am on December 19, 2013.

He said the group was riding two abreast and had just gone through the roundabout near the industrial estate, when a white Ford Focus came "far too close" to him.

Mr Burns said the car was about 10 to 20 centimetres away and he "felt a rush" of air as the vehicle went past.

He said the car went past the group in two to three seconds and he later stopped to record the car number plate and other details in his mobile phone.

Lavin, who represented himself, gave evidence in his defence and said he drove along that route three to four times a week.

He said he "did not do it on purpose", but he could not recall driving too close to any cyclists that day.

Magistrate Simon Brown found the charge proven and said Lavin had "put the wind up" a group of cyclists.

Mr Brown convicted Lavin and imposed the standard penalty of a $140 fine and three demerit points.