A powerful earthquake rocked southern Iran on Monday, Iranian and US seismologists said, with media reporting one person was killed and three others injured.

The Tehran University Geophysics Department measured the quake at 6.1 on the Richter scale, state television reported. The US Geological Survey put it at 5.5 after initially classifying it as 5.7.

The temblor hit the town of Konar Takhteh in Fars province at 2:52 pm (1122 GMT) and was felt 175 kilometres (110 miles) away in the provincial capital Shiraz, state television and Iranian news agencies said.

"One person was killed and three others injured in the earthquake," ISNA news agency reported, quoting the province's head of relief operations Amir Taghizadeh.

"Damage is minimal and there is no need for concern," he said, adding the region is not built-up.

Previously, local Red Crescent deputy chief Mohammad Reza Afzali had said the quake was unlikely to have caused serious consequences as "the affected area is sparsely populated."

But "people are nervous as the quake was deep and lasted a long time," he told ILNA news agency.

The agency quoted a resident of Shiraz as saying the earthquake had sparked panic in the provincial capital, with people running out onto the streets.

Another Red Crescent official, Mehdi Mosalanejad, said the town of Kazeroon, 25 kilometres from the epicentre, had not suffered any damage but that rescue teams had been sent to Konar Takhteh to assess the situation.

Iran sits astride several major fault lines in the Earth's crust and is prone to frequent earthquakes, many of which have been devastating.

The deadliest in recent times was a 6.3-magnitude quake which hit the southern city of Bam in December 2003, killing 31,000 people -- about a quarter of its population -- and destroying the city's ancient mud-built citadel.