Carolyn Taylor claims she spent years developing leggings which are supposed to improve core stability for women, which she then patented in 2010 and licensed to manufacturers.

However, browsing online one evening the Bendigo-based physiotherapist and physiotherapy lecturer came across Lorna Jane's website and spotted leggings that were similar.

"Lorna Jane was selling leggings and shorts that were a very similar design to ours and they were claiming that their leggings improve core stability," Ms Taylor said.

"I was despondent and I went into their stores as well to see them.

"It's a bit galling to see a big company like that selling so much stock which is based on my original idea."

Lorna Jane disputes Ms Taylor's claims.

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Ms Taylor developed her product after treating people with lumbar pelvic problems.

"I was really interested in core stability issues and I was taping a lot of patients," she said, referring to the practice of physiotherapists using strapping to support patients.

"I was thinking at the time it would be really good to have something where you didn't have to have someone with expertise to tape them."

Ms Taylor also used supportive braces known as sacroiliac joint belts in her treatment and came up with the idea of incorporating the elements these braces into compression garments.

She started the patent process in 2008 and spent about $30,000 securing it but it was not until 2017 that Ms Taylor discovered the similar Lorna Jane products.

She consulted a lawyer and a patent attorney and tried writing letters to Lorna Jane but said she got "fairly short shrift" from the activewear company and so filed a claim with the Federal Court last month.

The claim identifies 68 Lorna Jane products that are infringing products including Lorna Jane's "booty support" tights, "diamond seamless" tights and "intensity core booty" tights.

Ms Taylor claims Lorna Jane was "flagrant" in its infringement and has been aware of her patent rights since at least June 29, 2018 but has continued to infringe the patent.

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In the claim Ms Taylor seeks permanent injunctions to stop Lorna Jane selling the products, an order to destroy the products and payment of damages.

Ms Taylor said she had spent about $20,000 in legal fees.

"That is why we got the patent in the first place to protect our idea and our invention," she said.

Lorna Jane is considered to be the biggest retailer in Australia's booming activewear market and is reported to generate revenues of over $200 million.

Founders Lorna and Bill Clarkson own 60 per cent of the company and private equity firm CHAMP ventures owns 40 per cent.

Mr Clarkson said Lorna Jane had been designing and manufacturing compressive and supportive Activewear since 1989 when Ms Clarkson started hand-making leotards and short tights for herself and for clients in her aerobics classes.

"Compression and support tights have been part of our business for the last 30 years, over 20 years before this patent was lodged," Mr Clarkson said.

"We are confused as to why the claim in regards to infringing on a patent from 2010 for pregnancy support garments and medical compression garments have been bought against us when there are many great Australian brands that design similar garments."

Mr Clarkson said he looked forward to defending Lorna Jane's position.

"It is upsetting that yet again Lorna Jane, the brand we have fought tirelessly to build over the last 30 years and continue to take from strength to strength, has again been made a target."

The initial hearing is scheduled for May 3, 2019 in the Federal Court, Melbourne.

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