Farmers have expressed their increasing concern at seeing thousands of tourists stream onto their sunflower fields, destroying paddocks and crops.

The tourists are not just trespassing when walking into the golden fields, but also leave rubbish behind and have been caught stealing sunflower heads.

Sunflower grower Craig Smith from Nobby on Queensland's Darling Downs said on some weekends he had to chase hundreds of tourists out of his paddock.

"They do a lot of damage just walking through the paddocks, knocking plants down, compacting the ground, breaking sunflowers off and taking them," he said.

Tourists flock to the southern Darling Downs with vast, golden fields of sunflowers. ( ABC News: Elly Bradfield, file photo )

Mr Smith said it has been an issue for the last two seasons and he believed social media had got a bit to answer for.

"The tourists are encouraged to come and take photos, and we are happy to have them come and take photos, but we are not happy with them walking all over our paddocks and dropping rubbish and taking sunflower heads — which I witnessed first-hand on quite a few occasions," he said.

Visits to the fields promoted

Many tourists travel hours to get to the fields to take selfies and photos, posing in the golden array of sunflowers.

Information centres in the area and social media promote visits to sunflower fields, providing directions on where to find the latest blossoming fields.

Southern Queensland Country Tourism's photo competition offered a $2,500 holiday as prize for the best photograph taken traveling in the region.

Farmer Craig Smith is disappointed that tourists destroy his sunflower crop. ( Supplied: Craig Smith )

As stated on their Facebook page in late January, selfies with sunflowers had taken centre stage in the competition.

The chair of the Australian Sunflower Association, Kevin Charlesworth, said that it was getting a bit over the top with tourists walking into the sunflower fields.

He suggested that farmers put up gates and start charging people to go in.

"The media has been doing a bit of a publicity thing on how pretty the sunflowers are, and they are pretty," he said.

"As a farmer you can't really blame people for wanting to take photos, but the people that are going onto that country need to understand they are trespassing.

"It would be nice to ask the farmer if you can go in. It's just like if you have a nice garden in your town allotment, if someone walks in you aren't going to be too happy, are you?

"So people just need to be aware of that and try to take the photo from a distance and be conscious of what they are doing."

Biosecurity risk small but important

Mr Charlesworth said although the tourists pose only a small biosecurity risk to the sunflower paddocks, it is there and something to think about.

"Most people are from town so they haven't been walking around in someone else's property or paddock where you are going to bring in weed seeds or diseases. But there is still a small risk," he said.

Mr Smith said some weekends he had to chase hundreds of tourists out of his paddock. ( Supplied: Craig Smith )

Mr Smith said there was a need for more education as most tourists have no idea why farmers grow sunflowers.

"Most of them (initially) think that we just cut the flowers off and sell them to the cut flower market, but they are very interested to know what the sunflowers are used for," Mr Smith said.

"There seems to be a need that perhaps there could be a market out there for the tourist to learn more about the sunflowers where we can encourage them to come into our paddocks, at a fee, and teach them a bit about the sunflowers and let them go home with a bit more knowledge."

While sunflower growers have been battling the tourists' impact they are facing tough times as the unstable Australian market leaves farmers in uncertainty.

Many have transitioned into growing mung beans, cotton and soy as a cash crop.

Mr Charlesworth said sunflowers have become a niche market as AWB Cargrill withdrew from the oilseed crush market in Australia two years ago.

"They are going into horse feed, birdseed and human consumption, so virtually no crush in Australia. You need to grow a premium product for a premium market," Mr Charlesworth said.

Mr Smith said there was a need for more education as most tourists have no idea why farmers grow sunflowers. ( Supplied: Craig Smith )

Mr Smith said they had to be willing to store sunflower products and have the time to await price changes as they can be very erratic.

"It can be $500 a tonne this week and $1,000 a tonne in a week's time," he said.