The bombs ripped through a bank and a government building on Tuesday, in a region that has seen intermittent bombings and rioting since April.
Mahmoud Ahmadinejad, the Iranian president had been due to visit the city on Tuesday, but his office said he cancelled the trip on Monday night because of poor weather conditions.
Mansour Soltanzadeh, head of the Ahvaz medical school, told the official IRNA news agency that eight people had been killed and 46 wounded in the two blasts that went off between 9.30am and 10am (0600-0630 GMT).
He said: "Two of the wounded had to have their legs amputated ... The legs of two teenage girls will most probably also need to be amputated in the Razi hospital because of deep burns."
Mohammad Jafar Samari, governor of Ahvaz, dismissed the idea that the explosions could have targeted Ahmadinejad's visit.
"The place where the bombs exploded was a long way from where the president had planned to make a speech," he said, adding there was no word yet on who planted the bombs.
Lebanon's al-Manar television, run by the pro-Iranian Hizb Allah group, reported earlier that the bombs had been intended to kill Ahmadinejad. Its Tehran correspondent said the president had called off his trip after a security tip-off.
State television said the first bomb in Ahvaz, dominated by ethnic Arabs and capital of the oil-rich Khuzestan province, exploded in front of a privately run bank, killing six people and injuring 15.
The second blast, in front of a government office for natural resources, injured nine people.
A police official told state television that "they are home-made bombs."
The official added: "A home-made bomb exploded inside a branch of the Saman bank, which is totally burned."
President Ahmadinejad was
scheduled to visit the area
Another news report said: "Emergency workers are looking for the injured and the dead inside the bank."
In October, another double bombing in Ahvaz killed six people and wounded more than 100.
Iran has blamed Britain in the past for the unrest, accusing British forces based across the border in Iraq for backing ethnic Arab separatists.
In October, Manouchehr Mottaki, the Iranian foreign minister, said the clerical regime had proof of British meddling.
"The information shows that Britain is seeking to create insecurity in our country by interfering in our internal affairs," Mottaki said at the time, also adding that the consequences "could be worrying for the British".
Britain has firmly rejected the allegations, part of a wider deterioration of relations between Tehran and London over suspected Iranian meddling in Iraq and the Islamic republic's disputed nuclear programme.