Coordinated bomb attacks have hit two luxury hotels in the Indonesian capital Jakarta, killing at least nine people, including foreigners, and injuring dozens more.

The first explosion is reported to have happened at the JW Marriott hotel in central Jakarta just a few blocks away from the Australian embassy at about 8.00am this morning (local time). A terrorist attack at the same Marriott Hotel in 2003 killed 12 people and left 150 injured.

Later there was another explosion on the first floor of the Ritz Carlton hotel, directly opposite, with windows being blown out of the hotel's restaurant.

"There were explosions heard from two separate places, one the JW Marriott, the other in the Ritz Carlton. We are still trying to check because right now we are still helping the victims," South Jakarta Police Chief Firman Santyabudi told Indonesian Metro TV.

Police and health ministry officials confirmed the death toll and also confirmed that the explosions were caused by "high explosive bombs". The health ministry said 48 people had been seriously injured.

National police spokesman Nanan Soekarna said 14 foreigners were injured but a list of the wounded at a nearby hospital included the names of 18 foreigners.

Reuters is reporting New Zealand man Tim Mackay is one of the foreigners that has been killed in the attacks.

A DFAT spokewoman says the embassy in Jakarta is urgently trying to confirm reports that at least two Australians have been injured and is seeking to establish whether any others have been hurt.

Just over 1,000 Australians are registered with DFAT as being in Jakarta.

The spokeswoman says the Government unreservedly condemns the attacks which appear to be premeditated and coordinated.

A caller to Fairfax Radio in Melbourne said his son, an Australian, was among the injured.

"He was in the building and all of a sudden there was a massive explosion and he was bleeding from the left leg," the caller said.

"From what I can gather the injury's not serious. He's lost his hearing in one ear but he thinks he will recover from that and he's on his way to hospital," he said.

ABC Indonesia correspondent Geoff Thompson says Australian embassy staff live at both hotels.

"There are Australian embassy officials staying in those buildings but preliminary checks suggest that no embassy staff have been hurt or otherwise," he said.

"I heard two sounds like 'boom, boom' coming from the Marriott and the Ritz-Carlton. Then I saw people running out," security guard Eko Susanto told AFP.

Police have sealed off the area near the Ritz-Carlton and the JW Marriott, an AFP correspondent said.

Witness Intan told TV One one of the explosions wrecked the lobby of the Plaza Mutiara building.

"I was having breakfast on level 16, I heard an explosion and went down to the first floor and it was a mess. I saw foreigners all bloody, about three to five of them, badly wounded," she said.

"I saw some people being carried into a Mercedes. There was a lot of them in there, they were having trouble closing the doors," a witness, who gave her name as Mery, told ElShinta.

Former Melbourne resident Sarah Writer lives near the Ritz Hotel in Jakarta.

"Jakarta's really just waking up to this news, it's very, very new," she told the ABC. "We're still trying to understand exactly what's happened.

"The local news is reporting the area is shut down, and for obvious reasons, the nearby buildings full of major corporate people are all evacuating and relocating.

"There are reports of fatalities, but this early on you don't know what's true and what's not, what's exaggerated and what's not, but it would surprise me if there aren't fatalities going on the local news coverage."

DFAT says officials in Jakarta are urgently trying to identify if any Australians have been injured in the explosions.

It says anyone with concern for family and friends in the area should first try to contact them directly before calling the Department's consular emergency centre. The number is 1300 555 135.

The explosions come two weeks after presidential elections in Indonesia.

Australia-Indonesia Business Council vice-president Ross Taylor says the hotels are popular with Western business people but there could be a number of reasons behind the attacks.

"Just recently some members of Jemaah Islamiah were released from jail," he said.

"There may not be any connection with that at all. And of course today was the confirmation that President Susilo Bambang Yudhoyono was formally re-elected as president. Now whether there are some links there we just don't know."

- ABC/Reuters/AFP