Ramp up aid to Syria: Plibersek

Syria, like Cambodia, could take decades to rebuild after years of fighting, the federal opposition warns on the fifth anniversary of conflict.

The federal government is under pressure from Labor to urgently increase humanitarian aid to Syria as the conflict clocks up a five-year milestone.

Opposition foreign affairs spokeswoman Tanya Plibersek, speaking at the launch of a photographic exhibition of Syrian refugees at Parliament House, said Australia's additional $25 million aid contribution paled in comparison to other countries.

"Australia's response to this disaster must be more generous," she said.