The Recruit: Until now, she was a nameless airwoman seeking accountability for years of abuse in the Air Force. Now, Mariya Taylor speaks out.

An Air Force servicewoman who suffered years of harassment must pay the offender almost $28,000 in legal costs.

Robert Roper sexually harassed Mariya Taylor for three years when they were based at the Whenuapai base in Auckland in the 1980s.

The attacks, in which she was locked in a cage, eventually drove her from the armed services and from New Zealand.

SUPPLIED Working as a driver at Whenuapai air base, Mariya Taylor was repeatedly assaulted by Sergeant Robert Roper.

Taylor went to police after Roper was convicted in 2014 for raping his two daughters, Karina Andrews and Tracey Thompson, and Cherie Ham.

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All three women asked for their name suppression to be lifted so they could speak out.

SUPPLIED Former air force sergeant Robert Roper claimed nearly $56,000 in court costs after being sued by Mariya Taylor.

Taylor sued the Defence Force and Roper for compensation, stating the Air Force failed to provide her with a safe place to work.

A High Court judge agreed she was ogled, groped and repeatedly locked in a cage by Roper, but found she had left it too late to file a claim.

The Defence Force and Roper then claimed legal costs from Taylor.

The Defence Force later withdrew its claim, but Roper sought costs of $55,638.50.

The case was heard by Justice Rebecca Edwards in the High Court at Auckland.

On Monday, Justice Edwards ruled Taylor must pay Roper $27,819.25.

Justice Edwards noted judges could exercise discretion in awarding costs, but that was not "unfettered" and had to be exercised in accordance with relevant legislation.

In particular, the legislation said the party that fails in a proceeding "should pay costs" to the party that succeeds.

"The starting point is that Mr Roper successfully defended the claim against him, and is therefore entitled to an award of costs," Justice Edwards said.

However, Justice Edwards declined to award Roper the full amount he sought as he denied assaulting or falsely imprisoning Taylor, which "absorbed some time at trial".

If he had admitted the charges, the trial would not have taken nearly as long and Taylor would have been relieved of some of the distress of describing the traumatic events in court, she said.

Taylor's lawyer asked Justice Edwards to decline to award any costs to Roper.

He argued Roper's conduct was "outrageous, disgraceful and deplorable" and that he had not suffered any penalty.

Justice Edwards said while there was no dispute Roper's conduct was "heinous", denying him costs to penalise him for his behaviour would not be legally sound.

"Costs should not be used as a backdoor means of granting relief to a plaintiff who failed to get their claim past the front door."

If costs were not awarded, it might send a message to others that they could embark on legal action that they were likely to lose and would be "immunised" from paying for it, Justice Edwards said.

Roper spent more than $100,000 in total defending the claim, and he would still be left with a "significant cost burden", she said.