More than 20 riders were suspended in midair for hours after a Knott's Berry Farm ride malfunctioned this afternoon.

Guests at the Southern California theme park were stuck on the Sol Spin ride after technical difficulties caused it to stop at about 2pm (local time), a park spokesperson said.

The 22 riders were evacuated from the ride by 4.30pm according to the ride manufacturer's and park's emergency procedures, the spokesperson said.

Two female guests were taken to a hospital "out of an abundance of caution", the spokesperson said.

Aerial TV footage showed riders suspended in the air in all different orientations, with some stumbling out of their seats after being lowered back to the ground. The Sol Spin brings riders up over six stories high on six independently spinning arms, according to the Knott's Berry Farm website.

County fire officials said they were at the park on standby that but the rider rescue was handled by park staff.