Greens Senator Sarah Hanson-Young has condemned the conditions for asylum seekers on Manus Island as the ''worst'' that she has seen.
Senator Hanson-Young is visiting the PNG island and told ABC radio that the living conditions for asylum seekers, including 34 children, was ''primitive and oppressive''.
''These are the worst living conditions in a detention centre that I have seen,'' she said.
Her comments come a day after it was reported that at least two Sri Lankan asylum seekers had drowned and a third was missing after their boat smashed into rocks and broke apart off the coast of Java as they made their way to Australia.
Twenty-two Sri Lankans on the boat were rescued by Indonesian authorities and taken back to Indonesia.
Boat arrivals have slowed recently because of monsoon season and it remains to be seen whether the offshore detention measures will work once sailing conditions improve.
Senator Hanson-Young said the asylum seekers on Manus Island were housed in tents or ''rundown'' dongas, some of which had only recently had doors put on.
''The heat is really getting to people,'' Senator Hanson-Young said. ''There is no air-conditioning and very little privacy.''
She praised the work of NGOs Save the Children and the Salvation Army were doing their ''utmost'' to help the detainees.
But she said she had real concerns about the prevalence of malaria, with reports a 10-year-old girl had contracted the disease despite malaria tablets being given to asylum seekers every day.
And asylum seekers also were suffering from conditions such as ulcers and scratches that has become infected.
When asked whether these conditions were no worse than those for PNG residents, Senator Hanson-Young said: ''The problem is that these people (asylum seekers) are prisoners. They have no freedom of movement. Every moment of their day is dictated by guards.''
Meanwhile, opposition immigration spokesman Scott Morrison, deputy opposition leader Julie Bishop and customs spokesman Michael Keenan are visiting Sri Lanka to investigate measures to combat people smuggling operations.
