A bull gored an Australian woman and left her seriously injured during the final bull run of this year's annual San Fermin festival in Spain.

Four other runners were treated in hospital for cuts and bruises.

The 23-year-old woman, identified only as JE, was gored in the back and suffered multiple rib fractures and damage to her right lung that left her in "very grave" condition after an operation at Navarra Hospital.

The Australian was struck by a massive Miura bull as she clung to wooden barriers outside the bull ring entrance in Pamplona, said regional health authority spokesman Javier Sesma.

It is very rare for women to be gored during the annual festival since most of the runners are men. Javier Solano, a San Fermin expert, said records showed only two other women had been injured by gorings in the recent history of the fiesta.

The four injured runners, who were tossed by bulls or fell as they ran were identified as a 39-year-old man from California, a 23-year-old man from Madrid and two men from Navarra. None of those injuries were serious.

Miura bulls, which can weigh 695 kilograms (1530 pounds), are renowned as Spain's largest and fastest fighting bulls, and yesterday's bull run was quick, taking 2 minutes, 16 seconds to cover 928 yards.

The San Fermin festival, which honours the patron saint of the city, dates back to the 16th century and is also known for its all-night street parties, where copious quantities of red wine from Navarra and Rioja are consumed.