Australia has sent a plane and a ship to help search for scores of people believed missing after a boat carrying asylum-seekers sank off Indonesia. The boat went down on Saturday 40 nautical miles off eastern Java. More than 30 people have been rescued but reports suggest the boat was carrying more than 200 passengers. Australia is also sending police to investigate who organised the voyage. Those rescued said the destination was Australia\'s Christmas Island. Most of the asylum-seekers were reportedly from Afghanistan and Iran. Survivors said the boat had been severely overloaded. It is the second time a boat carrying Australia-bound asylum-seekers has sunk in two months. \'Callous disregard\' Australia\'s Home Affairs Minister Jason Clare said search operations would continue through the day. \"The 48-hour window is closing, it\'s almost been two days since the boat was sunk... the water is warm, but it\'s very very rough,\" he told Australian media. Map locator Indonesian helicopters, a navy vessel and several fishing boats spent Sunday searching the area for any more survivors. One man told Australia\'s Daily Telegraph that the crew took life jackets and swam away, leaving the passengers to drown. \"They were all from Indonesia. We lost sight of them in the big waves and we never saw them again. We don\'t know if they were rescued,\" the man said. Mr Clare said that the police team were being sent at Indonesia\'s request. \"You\'ve got people smugglers that act with a callous disregard for human life and the only way to tackle this effectively if you\'ve got police forces in Australia and in Indonesia, police forces across the region, working very closely together,\" he said. Those who were rescued had spent several hours in the water and needed hospital treatment. Some told local officials they had paid several thousand dollars for passage to Christmas Island, which is Australian territory but lies close to Indonesia. Australia has a large asylum processing centre on the island. Last year, as many as 50 asylum-seekers were killed when their boat broke up just off Christmas Island in strong seas. Another Australia-bound boat sank off Indonesia in early November. More than 50 people were rescued but at least seven - and possibly more - people died. Australian politicians want to put in place a system of offshore processing for asylum-seekers - something that they say will deter people from making the dangerous journey to Australia by boat. But a government plan to swap asylum-seekers arriving by boat with 4,000 UN-recognised refugees from Malaysia was ruled unlawful, because Malaysia has not signed UN refugee conventions.