The board voted 2-1 on Wednesday to proceed on a controversial rule to limit litigation surrounding union elections. The board still plans to vote on provisions that would help speed up union elections, but limiting litigation could achieve the same goal.

Romney has included reforming the NLRB, an independent federal agency, as one of the first steps he would take as president.

"I have called for legislation that would guarantee workers and businesses at least one month to prepare for a unionization vote," the former Massachusetts governor said, applauding House Republicans for supporting similar legislation. 

Romney has pledged to support the secret ballot for workers in order to guarantee the option not to unionize, and pledged that as president he would appoint "people who are experienced and unbiased" to the NLRB.

Romney used the opportunity to criticize President Obama, who appoints the board, which is then Senate-confirmed. 

"Once again, America’s businesses and workers are paying the price for a President who cares more about rewarding his political allies than about fostering an environment for economic growth and job creation," he said in the statement.