The foreign ministry on Wednesday renewed its advice for Australians to avoid all "non-essential" travel to Turkey until further notice.

"We have received information suggesting that further terrorist attacks may be imminent in Istanbul, Ankara and other centres in Turkey," the ministry said, echoing a warning issued hours earlier by the British Foreign Office in London.

"Australians in Turkey should exercise extreme caution, particularly in commercial and public areas," it said.

At least 28 people were killed and 450 injured by twin human bombings in Istanbul on 20 November targetting the British consulate and offices of the London-based HSBC bank. The dead included Britain's consul in Istanbul and an Australian woman working at the consulate.

Five days earlier, two similar bombings had wrecked synagogues on the European shores of Istanbul, killing 25 and injuring 300.

The attacks have been blamed on Islamic radicals linked to the al-Qaida network.

The Australian foreign ministry had already upgraded its travel warning on Turkey following the 20 November blasts, urging its citizens to avoid travel to major Turkish cities.