President Barack Obama and first lady Michelle Obama are asking the public to help them develop projects for his new presidential centre on Chicago's South Side.

The Obamas are starting up a foundation website -- Obama.org -- in the hours before Donald Trump is inaugurated the 45th president.

Obama says the foundation's projects will be developed "all over the city, the country and the world." He asks Americans to "tell us what you want this project to be and tell us what's on your mind."

The foundation is developing Obama's presidential library and centre in Chicago.

The president also took the opportunity to say goodbye and ask the public for feedback on the POTUS Twitter account.

The Obamas met with president-elect Donald Trump on Friday morning before the official inauguration ceremony began.