The three TV regulars - along with castmates Jesse Tyler Ferguson and Eric Stonestreet - claim their current longterm deals with executives at 20th Century Fox TV are in violation of California labour laws, which state personal service contracts can last no longer than seven years.
They are asking a judge to declare their prior agreements null and void, allowing them to renegotiate fresh contracts with increased salaries.
The main castmembers, who are said to have made $60,000 (£37,500) each per episode for season three, reportedly rejected TV producers' recent offer of $150,000 (£93,750) each per episode and they are seeking a considerable increase in pay. They are also asking for more freedom to take on non-Modern Family work, an option which is said to be seriously limited in their current contracts.
A planned table read for the first taping of the upcoming fourth season had to be cancelled on Tuesday (24Jul12) as a result of the legal wrangle. The lawsuits were filed in Los Angeles on Tuesday.
Co-star Ed O'Neill is not part of the action - he reportedly has his own deal in place, banking more than $100,000 (£62,500)-per-episode.
News of the salary dispute emerges days after Vergara was crowned the highest-paid actress on U.S. television by editors at Forbes magazine.
According to The Hollywood Reporter, the award-winning comedy generated $165 million (GBP103 million) in advertising revenue for ABC bosses last year (11).