A PETITE P-plater who escaped punishment in a local court for drink-driving, despite having five previous offences, was fined and banned from driving last week by an appeal judge.

Sydney waitress Lourdes Rahe, who weighs 48kg, recorded a blood alcohol reading of 0.08 after driving through a red light without P-plates in July last year.

It was her fifth driving offence, yet Waverley magistrate Lee Gilmour dismissed the charge with a section 10 - usually reserved for first offenders.

Last week, Judge Ron Solomon said Ms Gilmour should not have "contemplated a section 10'', given the number of recent fatalities involving young drivers.

He convicted Rahe, fined her $500 and disqualified her from driving for six months after finding she had lied about how much she had drunk.

Rahe told the Court of Appeal that after finishing work at La Vecchia Cucina restaurant in Potts Point, she drank two glasses of pink champagne.

She was stopped by police at 1.30am on July 30 after she drove through a red light.

Her lawyer, Chris Watson, hired pharmacologist Professor Graham Starmer to do laboratory tests based on Rahe's body weight and the alcohol she claimed to have consumed.

He found Rahe would have been entitled to assume she was safe to drive.

But Judge Solomon found Rahe had "lied to police and this court'' about how much she had drunk that evening.

It was also revealed Ms Gilmour had failed to consider Rahe's poor driving record.