The Air Force has programmed four of its air defense radars to closely monitor the southern border following the encroachment of at least one Australian naval ship into Indonesian waters to turn back asylum seeker boats.

'We are concentrating on four radars in Timika, Merauke, Saumlaki and Buraen, which face Australia,' Air Force chief spokesman Air Commodore Hadi Tjajanto told The Jakarta Post over the phone on Wednesday.

'So if we notice any border violation, Makassar will be ready. Australia is reachable from there.'

Hadi was referring to the 11th squadron in the South Sulawesi provincial capital, which has 16 Russian-made Sukhoi Su-27/30 Flankers. The 11th squadron is based at Sultan Hasanuddin Air Force Base.

The Flankers have a maximum range of some 3,000 kilometers while the sea border lies some 1,000 km from Makassar. With a speed of Mach 1, or the speed of sound, the Flankers would take a little over one hour to reach the border.

When asked about the readiness at Iswahjudi AFB in Madiun, East Java, which lies some 900 km southwest from Makassar, Hadi sait it was 'still normal in Madiun'.

He added that no further border violations had been detected.

Separately, Coordinating Political, Legal and Security Affairs Minister Djoko Suyanto said that Australia, under the administration of Prime Minister Tony Abbot, must acknowledge and understand Indonesia's sovereignty and should not violate it.

"Asylum seekers that have entered a country, including Australia, must be managed according to the UN Convention," he asserted in a written statement as reported by Antara news agency on Wednesday.

The country concerned, meanwhile, must also handle the problem in cooperation with the United Nations High Commissioner for Refugees (UNHCR) or the International Organization of Migration (IOM), he added.

Djoko's office has strongly criticized the encroachment into Indonesian territory by at least an Australia naval ship.