Barack Obama has only 100 days left to serve as president - but plans to approach them the same as his previous seven-and-a-half years in office.

And there is no time to relax for the 55-year-old, who still hopes to make headway on a Trans-Pacific Partnership trade deal as well as Supreme Court issues.

With the US election taking place on November 8, Obama now has just over three months left in the job since first occupying the Oval Office in 2009 (he was elected in 2008).

Asked about Obama's feelings going into the final stretch, White House press secretary Josh Earnest he wasn't sure if his even boss knew the final countdown clock had begun.

But, he added, the president "is looking forward to making the most of every moment that's remaining".

"The president is approaching the final 100 days the way that he approached the previous seven and a half years or so, which is seeking to make the most of every remaining opportunity to use the power of this office to advance the interests of this country, to fight for middle-class families, and to keep our country safe," Earnest said.

"Part of that is advocating for a successor who is committed to those values and those principles".

When asked whether Obama was sleep-deprived, Earnest quipped that he was "looking forward to sleeping longer than usual".