One man was arrested after an extensive man hunt and multiple police chases, but two men are still on the run following the incidents at Jervis Bay.

Police have urged members of the public not to approach the men, described as having dark complexions and aged in their early 20s, one with a slim build and the other with a large build, as they may still be armed.

The men are alleged to have robbed a jewellery store on Owen Street in Huskisson at gunpoint around 5pm on Tuesday, during which the store owner was assaulted. Police allege they fled in a stolen car with cash and jewellery.

About five minutes later, a 43-year-old woman was forced from her car on St George Avenue after pulling over to assist the men, according to a witness, who said the woman "put up a really good fight".

The witness said she was driving on St George Avenue when she saw a black car travelling "very, very fast" hit the curb and come to a rest against a pole.

She pulled over about 30 metres away intending to offer assistance to the driver, she said, in the meantime another Good Samaritan - the 43-year-old woman driving a silver Toyota - pulled up behind the black car.

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A third car, coloured white, then pulled up behind her car.

"I saw the driver [of the black car] open the door, drag the woman out, take her behind the car and take her either to the front passenger seat or the back seat," the witness said.

"It looked like he was trying to bundle her inside. She was putting up a fight. She was screaming.

"Later on I realised one of the guys from the [white] car pulled up behind had gotten out, he started hitting her. They both started laying into her."

"She put up a really good fight, they knocked her to the ground."

The witness said the man abandoned the crashed car and departed in the injured woman's silver Toyota.

She said the white car made a U-turn before speeding down the road past the injured woman and herself.

When the witness went to the injured woman's aid, she said she saw a knife with a blade 8-10 inches long on the ground nearby.

She said the woman was in shock and told her that her legs had been run over.

NSW Ambulance paramedics were called to the aid of the woman. She suffered injuries to her pelvis and lower legs, and shock, and was taken to Shoalhaven Hospital in a stable condition.

Police started a manhunt in the area in search of the three men and the vehicles. One car was found dumped and burnt out in nearby Bayswood Avenue.

Officers initiated a pursuit of a car on Jervis Bay Road which was terminated due to the manner of driving.

An officer approached the car at Tomerong a short time later as the three men exited the vehicle, one producing a gun and pointing it at a police officer.

"The police officer has challenged that offender and also sought cover from the firearm which had been produced," a police spokesman said.

Police say the men fled into bushland and a major search of the surrounding area commenced, involving local police, the State Protection Support Unit, Tactical Operations Unit, Dog Unit and Police Rescue.

In the early hours of Wednesday, police tried to stop a vehicle, pursuing the car to Nowra where the men again fled on foot.

About an hour later, at 2am, police arrested a 37-year-old man after an alleged home invasion and third aggravated car theft in Morton Parade, Nowra. He was taken to Nowra Police Station where he currently remains in custody.

Officers are continuing to search for two other men and are asking anyone with information about their whereabouts to come forward.