Nikki Haley and Ron DeSantis get chance to provide alternative to Donald Trump

Republican presidential candidates, Florida governor Ron DeSantis, and former South Carolina UN Ambassador Nikki Haley (File/AP)

Nikki Haley and Ron DeSantis will be alone on the debate stage for the first time as they wage an increasingly contentious push to become the primary Republican alternative to Donald Trump.

With other contenders absent, the stakes are high for both Ms Haley, the former UN ambassador, and Mr DeSantis, the Florida governor.