Bulldogs NRL halfback Ben Roberts has been fined more than $2000 after pleading guilty to assaulting police and resisting arrest.

Officers used capsicum spray to subdue Roberts in February this year after an altercation outside the Glasshouse Tavern in Wollongong, south of Sydney.

A Bulldogs club doctor said Roberts was heavily concussed as a result of the incident, with considerable grazing and bruising to his face and head.

The Kiwi international was charged with assaulting a police officer, resisting arrest, common assault and refusing to comply with a police direction.

Roberts, 23, today entered guilty pleas to each of the charges in Wollongong Local Court.

He was fined $2200 and ordered to pay court costs.

Court documents said Roberts flexed his muscles at police on the night of the incident and said: "Do you really want me to unleash these on you?"

This is not the first time Roberts has been in trouble with the law.

In July last year, Roberts pleaded guilty to drink driving after recording a blood-alcohol level of .03 while on a provisional licence, which has a zero alcohol limit.

He was fined and disqualified from driving for three months - a conviction later overturned on appeal.

Roberts was also stood down from first grade for one week in July this year after the Bulldogs fined him $5000 for breaching the clubs' code of conduct for his involvement in a fight at a night club in Cronulla, in Sydney's south.

AAP