By Carrie Dann, NBC News

(NBC) - The simmering feud between the daughters of former Vice President Dick Cheney over same sex marriage has reignited on social media.

Mary Cheney and her wife Heather Poe took to Facebook to express their disappointment after Liz Cheney  - a GOP candidate for Senate in Wyoming - repeated her opposition to same sex marriage during a television interview.

"Liz - this isn't just an issue on which we disagree - you're just wrong - and on the wrong side of history," Mary Cheney wrote.

In a separate Facebook post, Heather Poe called her sister-in-law's comments "offensive."

"Liz has been a guest in our home, has spent time and shared holidays with our children, and when Mary and I got married in 2012 - she didn't hesitate to tell us how happy she was for us," Poe wrote on the social media site. "To have her now say she doesn't support our right to marry is offensive to say the least."

During an interview on Fox News Sunday, the elder Cheney sister said she believes in the "traditional definition of marriage,"  adding that she loves her sister and her family.

"This is just an issue on which we disagree," she added.

The issue of same sex marriage has dogged Liz Cheney in her Senate bid, which pits her against incumbent Republican Mike Enzi. The conservative group American Principles Fund has been airing ads painting her as soft on gay rights issues.

One such commercial shows a 2009 interview on MSNBC during which Cheney voiced opposition to a constitutional amendment that would have banned same sex marriage and praised the State Department for offering benefits to same sex partners.

On Sunday, Cheney called on Enzi to "renounce" that ad.

"Senator Enzi's friends and supporters are running a really scurrilous ad in Wyoming," she said on FOX News. "And the senator said many times that he doesn't believe in gutter politics."

The latest war of words comes just over two months over Mary Cheney said her sister was "dead wrong on the issue of marriage."

In a Facebook post in August, Mary Cheney added that "freedom  means freedom for everyone ... That means that all families — regardless of how they look or how they are made — all families are entitled to the same rights, privileges and protections as every other."

Vice President Dick Cheney, the father of both women, said in 2009 that he supports legalizing same sex marriage if the states - rather than the federal government - codify it.

Mary Cheney and Heather Poe married in 2012 in Washington DC, where same sex marriage has been legal since 2010. They have two children.