(Reuters) - Businesses and Senate Republicans forced a courtroom showdown with President Barack Obama's administration on Wednesday, asking a U.S. appeals court to invalidate his surprise appointments to a labor board 11 months ago.

Lawyers with the groups and for Obama's Justice Department argued for more than an hour over whether the president exceeded his authority by filling the vacancies while the Senate was out of town but potentially available to act on them.

The case is a test of the president's ability to make appointments during a Senate recess, a power that bypasses the Senate's usual ability to block nominees and that dates to the U.S. Constitution of 1787. Unlike nominees confirmed by the Senate, recess appointments are only for up to two years.