Heather Hardy has hit out again at the disparity in pay between male and female boxers  ahead of her super fight with Amanda Serrano.

The 37-year-old, who has been extremely vocal in the past about the gender pay gap, will defend her WBO World Featherweight Title in the main undercard fight before Devin Haney against Zaur Abdullaev in New York.

And while Hardy is appreciative of the fact she is receiving the highest purse of her career from Eddie Hearn's Matchroom Boxing, she remains disappointed by how little it is in comparison to male fighters.

She said: "It's a career-high pay day for me for both boxing and MMA, so that's nice.

"But with that I have to say that me and Amanda are selling out the show and without it sounding like 'oh, all Heather does is complain about the pay', men would be making in the millions for this fight and we're not even making six figures.

"We could have headlined for sure. We're the ones responsible for all the ticket sales, right. Of course we could have headlined."

The Brooklyn-born fighter is undefeated as a professional boxer with a record of 22-0, and has won two of her four MMA bouts.

Meanwhile, Serrano has lost just once in 38 pro fights - a defeat which came back in 2012 - and is widely considered one of the most dangerous boxers in the sport having knocked out nine of her last 11 opponents.

Yet despite the pedigree both women possess, Hardy believes more needs to change before women can begin to see the same kind of lucrative money on the table.

"The problem is you still have most boxing promoters investing their money in men," she said.

"Eddie Hearn stands to make more money off of Devin Haney than me and Amanda, and until women get to a spot where we're producing enough money for promoters then they're not really going to be interested in caring where we are on the card.

"Me and Amanda's own resumes got us to this co-main event status. Knowing that we'll pull our own weight, sell their own tickets, get the media buzz, people will talk about it."

The winner of Hardy-Serrano has signed to take on Katie Taylor within the next six months, so that is what Hardy is looking towards given it is one of the biggest fights to be made in women's boxing.

"It's a six figure payday, so that's my incentive," she said.

"I'm a single mum. I have a kid going to college in two years. I need to pay that tuition.

"I'm so used to being the one to set the table. I'm the name, everyone knows me, they come and sit at my table and I feed them.

"If there's good food there, I'm going. Katie's got a nicer table than I've got. I'm coming."