The Australian government has warned its citizens against traveling to the Turkish cities of Ankara and Istanbul because of the terrorist threat.

Foreign Minister Julie Bishop said the heightened travel warnings on Thursday follow the deaths of more than 80 people in four separate suicide bombings in the two cities this year.

Australians are advised to "reconsider your need to travel" to the cities — the second-highest danger warning on a four-tier scale.

Provinces of Batman, Bingol, Bitlis, Gaziantep, Hakkari, Hatay, Kilis, Mardin, Sanliurfa, Siirt, Sirnak, Tunceli and Van had previously carried the same travel warning.

Turkey overall carries Australia's second-lowest travel warning, although Australians are advised not to travel within 10 kilometers (six miles) of the Syrian border.