Former Vice President Joe Biden has publicly supported the US women's soccer team after their equal pay case was dismissed by a judge.

The women's side had been suing US Soccer for around $66 million in damages in an equal pay case, but judge R Gary Klausner ruled on Friday it won't make it to trial.

Biden tweeted: “Don’t give up this fight. This is not over yet."

He is the most likely candidate to win the Democrat ticket to run for president against Donald Trump in November. 

Biden added: “To US Soccer: equal pay, now. Or else when I’m president, you can go elsewhere for World Cup funding.”

Although the judge ruled against the equal pay claim, he did allow their claims of discrimination based on travel conditions and medical and training support, to move forward. 

On Thursday, co-captain of the team Megan Rapinoe conducted an Instagram live with Biden and his wife, Jill.

Rapinoe threw her hat into the ring to be his vice president, she said: “I don’t want to put you on the spot.

“I think I could still play soccer and do this. But if you need a vice-president, I’m just saying I’m available for an interview. We can talk logistics and the details. Put it on your list.”

Biden has promised to choose a woman as his running mate but did point out that Rapinoe would have to take a pay cut to take the position.

“I'm into that,” the World Cup winner said.