Billy Ray Cyrus has accused his estranged wife Firerose of waging a "campaign" to isolate him from his family.

The Achy Breaky Heart singer, who filed for divorce from his wife after seven months in May, made the claim in additional legal documents on Monday.

"Since the Plaintiff filed his initial complaint, he discovered that the Defendant had been conducting a campaign to isolate the Plaintiff from his family," reads the new complaint obtained by E! News. "He has discovered that the Defendant, unknowingly to Plaintiff, blocked at least one (1) of his daughters from being able to contact him on his phone(s) or electronic devices."

Billy Ray, 62, shares daughters Miley Cyrus, 31, and Noah Cyrus, 24, with his ex-wife Tish Cyrus. He is also the adoptive father of Tish's daughter Brandi Cyrus, 37, and has three sons.

Billy Ray and his family have been subject to estrangement rumours in recent years and Miley fuelled the speculation when she didn't mention her father in her Grammys acceptance speech in February.

During an interview on David Letterman's Netflix show, My Next Guest Needs No Introduction, earlier this month, the Flowers hitmaker side-stepped a question about the estrangement rumours and said she inherited her "narcissism" and "great hair" from the country star.

When asked if Billy Ray was her hero, Miley replied, "I mean, honestly, my mom is my hero. My father... I'm grateful for - first, his genes. My dad has great hair, and I got that."

Elsewhere in his new complaint, Billy Ray alleged that Firerose, real name Johanna Rose Hodges, lied about her last name and about being married twice before.

He is seeking an annulment of the marriage on the grounds of fraud.