Roger Federer demonstrates his elite reflexes by rallying a tennis ball off the wall from short distance. (0:59)

Serena Williams' coach Patrick Mouratoglou has called on tennis governing bodies to come together and devise a way of helping lower level professionals struggling financially due to the coronavirus shutdown.

The tennis season was halted in early March due to the pandemic, leaving players in the lower tiers who solely depend on tournament winnings without the opportunity to earn a living.

Coronavirus: Postponements and cancellations in sport

In a letter posted on Twitter and addressed to the tennis community, Mouratoglou said the current situation showed how "dysfunctional" the sport was.

"Unlike basketball or football players, tennis players aren't covered by fixed annual salaries. They're independent contractors," he said.

My letter to the tennis community to raise awareness about the current situation of players out of the Top100. pic.twitter.com/mFTIECxOFL — Patrick Mouratoglou (@pmouratoglou) April 7, 2020

"They're paying for their travels. They're paying fixed salaries to their coaching staffs, while their own salaries depend on the number of matches they win."

While tennis rewards top players handsomely those in the lower echelons often struggle to make ends meet.

Mouratoglou, who started working with Williams in 2012 and has guided her to 10 of her 23 Grand Slam singles titles, said the top players deserved everything they earned.

Patrick Mouratoglou calls for the tennis bodies to do more to help players who are struggling due to the coronavirus pandemic. Photo by Daniel Pockett/Getty Images

The men's ATP Tour and the WTA, which runs the women's circuit, suspended all tournaments until mid-July after countries started locking down their borders to contain the spread of the flu-like virus.

He added: "However, I find it revolting that the 100th-best player of one of the most popular sports in the world -- followed by an estimated one billion fans -- is barely able to make a living out of it."

A 2018 International Review Panel report commissioned to address betting and integrity issues said that players in the lowest tiers were susceptible to corruption because of the difficulty in making a living, with only 250-350 players earning enough to break even.

Georgia's Sofia Shapatava, the world's 375th ranked women's singles player, has started a petition seeking assistance from the International Tennis Federation for lower-level professionals.

Many others have joined her to voice their concerns about the financial hardships players face during the shutdown.

The WTA and the ATP said they were working to boost players' earnings when the sport resumed and might extend the 2020 season to allow more tournaments to be held.

Mouratoglou said it was crucial to keep lower-level players in the game.

"We all rely on those governing bodies, who have the power to protect the professional tennis economy and hold social responsibility," he added.

"We can't leave lower-ranked players behind anymore. This isn't right. Tennis needs change. Let's use this free time to start a discussion."