Dolly Parton’s sister has asked fans to pray for the American country singer, who last week postponed a forthcoming Las Vegas residency due to unspecified health issues.

The 79-year-old country music legend has delayed the December concerts, telling fans she needs “a few procedures” to deal with ongoing “health challenges”.

“Last night, I was up all night praying for my sister, Dolly,” Freida Parton wrote on Facebook. “Many of you know she hasn’t been feeling her best lately.

“I truly believe in the power of prayer, and I have been lead to ask all of the world that loves her to be prayer warriors and pray with me.”

Freida ended her message on an upbeat note.

“She’s strong, she’s loved, and with all the prayers being lifted for her, I know in my heart she’s going to be just fine,” she wrote.

“Godspeed, my sissy Dolly. We all love you!”

A spokesperson for the singer told CBS News, the BBC’s US partner, that she will be posting a social media message on Wednesday that “will address everyone’s concerns”.

Parton had been scheduled to perform six shows at The Colosseum at Caesars Palace in December.

But she postponed the gigs until September next year, explaining she wouldn’t have enough time to rehearse for them.

Parton did not disclose the nature of her health issues, but she was recently forced to pull out of a Dollywood event after being diagnosed with a kidney stone that she said was causing “a lot of problems”.

Earlier this year, she lost her beloved husband Carl Dean after nearly 60 years of marriage.

She later dedicated a new song, If You Hadn’t Been There, to his memory.

The musician is best known for a string of country crossover hits including Coat of Many Colors, I Will Always Love You, 9 To 5 and Jolene.

Her Las Vegas stint would have been her first visit to the Strip since the 1990s, when she performed alongside her Islands In The Stream duet partner, Kenny Rogers.