The heat is on in the Arkansas Senate race between Republic Rep Tom Cotton and Democratic Sen Mark Pryor and in the last few days, things got a little tense over faith.

Pryor went on the defensive after Cotton suggested he was just a Sunday Christian.  

Cotton made the comments during a TV interview relating to the Supreme Court's Hobby Lobby ruling in which he agreed with the court's decision that family-owned companies should not be forced under Barack Obama's healthcare law to provide insurance coverage for contraception.

Cotton agreed with the ruling on the basis that it would have hindered the right of Christians to live according to their beliefs.  

"Barack Obama and Mark Pryor think that faith is something that only happens at 11 o'clock on Sunday mornings," he told KNWA. 

"That's when we worship, but faith is what we live every single day, and the government shouldn't infringe on the rights of religious liberty." 

Pryor has been open about his Christian faith and appeared in an advert last year holding a Bible and saying: "I'm not ashamed to say that I believe in God.  And I believe in his word." 

He was offended by Cotton's comments and released a statement in which he suggested Cotton keep the rhetoric to politics. 

"I'm disappointed in Congressman Cotton's deeply personal attack on me.  He and I may disagree on issues, but for him to question my faith is out of bounds," said Pryor. 

Cotton in turn followed up with a statement in which he clarified that his comments were about the health law and not Pryor's faith. 

He said he respected Senator Pryor as someone who practises their faith with "commendable openness".  

He added: "But I wish he would respect Arkansans' right to practice our faith." 

Arkansas is one of the states where Republicans are hoping to win seats, alongside Louisiana and North Carolina.  They are pushing hard to gain six seats in order to secure majority control of the Senate.