Cyrus, 23, and Hemsworth, 26, did consider saying their vows at a small summer beach ceremony in the Hunger Games star's native Australia but that plan is now off.
The source said: "Miley is pretty adamant about having a small, private ceremony. But Liam wants a really big wedding, so I'm sure they'll come to a compromise."
Miley's dad Billy Ray Cyrus has publicly stated he would love to officiate his own daughter's nuptials after getting a taste for it from his role playing a washed-up country music singer who finds himself pretending to be a minister in new TV show 'Still the King'.
He previously said: "They're really happy together right now. They know if they need a preacher, they've found one."
Miley and Liam broke off their first engagement in 2013 after three years of dating before rekindling their relationship several months ago.
- Bang! Showbiz