Travellers are being coerced into performing sexual acts in return for farm employers signing off on backpacker visa applications, Queensland's Anti-Discrimination Commissioner (ADCQ) says.

Kevin Cocks has told the ABC some employers are withholding signing off on visa applications in order to manipulate travellers.

Backpackers who have come to Australia on a one-year Working Holiday (subclass 417) visa are required to undertake at least three months of work in regional or rural Australia in order to qualify for a second year.

Upon completion, farmers or contractors are obliged to sign off on visa application paperwork to confirm the applicant has finished farm work.

But Mr Cocks said some employers saw the arrangement as an opportunity to pressure backpackers into sex.

"Young women are asked for sexual favours to get their visa signed off," he said.

"Often the contractors provide accommodation as well, so women are being put in quite vulnerable situations.

"We've had a number of direct or indirect issues raised with us by the community members, police and other government agencies.

"At least a dozen over the past 18 months, and that's just in the area that we've worked in [the Lockyer Valley in south-east Queensland].

"What's been indirectly reported to us is more serious criminal sexual exploitation."

A Queensland Police spokesman confirmed some farmers were abusing their right to sign off visa applications by harassing backpackers.

"People on visas are sometimes placed in vulnerable situations where they are open for manipulation by employers," the spokesman said.

"Often people want [police] assistance in escaping a bad situation, but it is not unusual for no complaint to be made once backpackers are out of the situation."

In order to satisfy the only requirement to employ backpackers seeking a second Working Holiday visa, the farm has to be located in an eligible — usually isolated — postcode area.

The Fair Work Ombudsman said it was conscious "an overseas worker's vulnerability whilst in Australia can be increased by factors such as the remoteness of working locations and dependence on the employer to obtain eligibility for a second-year visa".

Farmers refusing to sign 'not unusual'

In a bid to secure her second year in Australia, German backpacker Daphne took on farm work in central New South Wales.

A backpacker hostel sent her to various fruit-picking farms, including one where female workers were separated from males and taken to the "far corner" of the property.

"[Some] were pretty bad. Even the hostel staff originally told us, 'Stay away from this guy, stay away from that guy, because they are going to touch you'."

Daphne said it was not unusual for some farmers to refuse to sign off on completed farm days.

"The last week, when I got to the farm, I asked straight away, 'Can you sign it (the visa application), I'm going to work on your farm today'," she said.

"He (the farmer) went straight away, 'I'm going to sign this, but only if you sleep with me'.

"I walked off from that job on that day."

With only limited time left until her first year visa expiry date, Daphne decided to put up with the harassment.

"I wanted to leave but the problem was that I couldn't because I needed that visa," she said.

From 'extremely nice' to 'really nasty'

Mia (not her real name), an Australian traveller who worked alongside backpackers on farms, accepted a job on a remote cattle station in northern Queensland.

She remembered her first day starting off as "extremely nice", but as soon as she was left alone with the farmer he became "inappropriate and touchy", making suggestive comments and promising her horses.

Second-year 417 visa conditions More than 194,000 Working Holiday visas were granted in the 2014-15 financial year; 38,019 were second-year visas Approved industries for regional work are: plant and animal cultivation; fishing and pearling; tree farming and felling; mining; construction. Applicants can work in separate fields for a number of businesses The following postcode areas are not eligible for 417 visa: ACT, Sydney, Melbourne, Perth and surrounding areas, Newcastle, the Central Coast, Wollongong, Greater Brisbane, the Gold Coast

"In the car, he would put his hand on my leg and when I was shutting gates he would come behind me, get really close and put his arms around me," she said.

"He was saying things like 'you will get far' and benefit from being close to him and offered to watch movies in his room.

"He just said if I play my cards right and stay he will give me a couple of horses."

But it was after she expressed her wish to leave that she really felt intimidated.

"When I told him I wasn't staying he was really nasty; he just said that he thought I was better than that and to get out of his sight," she said.

Fearing the farmers would cause her more trouble if she went to the police, Mia did not report the harassment.

Backpackers 'fearful' of issuing complaint

Farmers whose conduct has been reported to police and immigration officials are not blocked from continuing to employ backpackers for visa purposes.

A Department of Immigration spokesperson said: "Any Australian employer can sign an Employment Verification Form for a Working Holiday visa holder."

"While the department has no regulatory ability to exclude Australian employers from employing working holiday visa holders or verify their employment, the department does maintain information on employers of known integrity concern and screens and scrutinises working holiday visa applications accordingly."

When asked how many farms the department had identified as being of concern in the past 12 months, the spokesperson said: "As there are ongoing investigations of farms identified to have working holiday visa integrity issues, it would be inappropriate to comment further."

An AgForce Queensland spokesperson said "working on Australian farms is usually a rewarding experience for young people on a working visa" and called for "anyone involved with Australian agriculture who does something illegal to be reported to police and dealt with accordingly".

But Mr Cocks said while backpackers did inform the ADQC about having experienced sexual harassment and abuse in farms, they often remained "fearful" when asked to issue a complaint.

"One is that they fear they will not have their visa renewed. Or they don't fully trust the authority because where they come from there may be corruption in their country," he said.