Romney, who is Mormon, has not attended Family Leader events in the past, despite most of the other GOP candidates’ participation, and does not plan to attend the upcoming Family Leader’s Thanksgiving Family Forum.

Vander Plaats, considered a kingmaker in the first-voting state, warned Romney earlier in the week not to “walk away” from the type of voters who would be at the event.

Presidential hopefuls Newt Gingrich, Rick Santorum, Michele BachmannMichele Marie BachmannBoehner says he voted for Trump, didn't push back on election claims because he's retired Boehner: Trump 'stepped all over their loyalty' by lying to followers Boehner finally calls it as he sees it MORE, Ron Paul, Rick Perry and Herman Cain all plan to be at the event on Saturday.

Iowa Gov. Terry Branstad (R) on Wednesday also criticized Romney for not spending enough time in the state, calling it “a big mistake.”

Romney is “trying to downplay it and keep the expectations down. But if he comes in fifth or sixth here I think it really damages his campaign nationally. Iowa voters are spoiled by attention, and if you have a candidate who does not take them seriously, I think they'll punish him,” Branstad said at an energy forum.

“I think what will happen is what happened in 2008. He's been in this position before. He's been on top of polls only to find his campaign tanking and sucking air,” Vander Plaats told Fox News. "If Romney loses Iowa, I think it will be a huge dent to his campaign. It will be just like fours years ago, and New Hampshire will be up for grabs.”

New Hampshire is widely considered the state with Romney’s strongest base of support.

Romney’s campaign has ramped up his Iowa presence in recent weeks after taking a mostly hands-off approach there. Romney’s wife, Ann, has campaigned in the state on his behalf several times and Romney has held several town halls. He plans to be back in the state for campaign events next week, following the Family Leader event.

Romney currently polls in a four-way tie with Cain, Paul and Gingrich in Iowa, according to the latest Bloomberg News poll this week.

Iowa’s first-in-the-nation caucus is scheduled for Jan. 3.