The President of the United States said Tuesday that a former Arizona sheriff, who was found guilty of criminal contempt of court, would be "just fine", although he stopped short of pardoning the former law enforcement officer.

"I'll make a prediction. I think he's going to be just fine," US President Donald Trump said Tuesday during a rally in Phoenix, Arizona.

The US president said last week that he was "seriously considering" pardoning the former Arizona sheriff, Joe Arpaio.

Trump was initially expected to announce the presidential pardon for the ex-sheriff during the rally in Arizona but decided against it.

"I won't do it tonight because I don't want to cause any controversy, but Sheriff Joe can feel good" Trump said, hinting at a future presidential pardon.

Thousands of protesters gathered outside the Phoenix Convention Center where Trump held the rally, with police using tear gas in attempts to disperse the crowds.

Arpaio, who served as the Maricopa County Sheriff between 1993 and 2016, was found guilty on July 31 of criminal contempt of court by a federal judge in Arizona.

The judge ruled that the 85-year-old ex-sheriff was guilty of intentionally violating orders in a case involving racial discrimination against Hispanic drivers.

Arpaio, whose sentence is expected to be announced on Oct 5, could face up to six months in prison.

He became a notorious public figure when he established "Tent City", a temporary jail where inmates served their sentences outdoors in the extreme weather conditions of Arizona's desert.

His well-publicized policies and actions against undocumented immigrants brought him national and international attention.