Former US president George H.W. Bush is in intensive care in hospital after taking a turn for the worse with a "stubborn fever," a spokesman said.

"He's had a series of setbacks now that have landed him in guarded condition in the intensive care unit," spokesman Jim McGrath told AFP.

The 88-year-old was first admitted to Methodist Hospital in Houston on November 7 for bronchitis treatment and released on November 19. But he was readmitted on November 23 after his cough flared up again.

Doctors had initially hoped to have the elder statesman home for Christmas, but he was instead forced to spend the holiday in hospital, where he was joined by his wife Barbara, son Neil and grandson Pierce.

"I wouldn't say he was able to celebrate it in the traditional sense," McGrath said. "His family was with him, and he's conscious and he's able to engage in humorous banter with his doctor."

Bush, a Republican, was in the White House from 1989 to 1993 and sent US forces into Iraq in the first Gulf war after Saddam Hussein's forces invaded Kuwait.

During his time in public service, he also served as vice president, congressman and director of the Central Intelligence Agency (CIA). He is the father of former president George W. Bush.