Australia and Japan must work together to address the worsening security situation in Sri Lanka, former U.N. Undersecretary General Yasushi Akashi said Monday.

"I think this emerging crisis is a matter of grave concern for Australia as well, and I think we must put our heads together as to what we can do to lessen the alarming developments in Sri Lanka," Akashi said in Sydney.

The political leader of the Tamil Tigers, S.P. Tamilselvan, pulled out of security talks last month amid worsening violence at home.

"The situation is becoming very tense and there is the danger of the resumption of a full-scale war," Akashi said.