THE Opposition Leader, Tony Abbott, has dismayed welfare services by telling them that governments cannot stop people from being homeless ''if that's their choice'' and declining to match the Rudd government's goal to halve homelessness by 2020.

In comments made at a Catholic social services conference in Melbourne last week, Mr Abbott said that while wanting to boost services for the homeless, one of the difficulties with making commitments over targets was their achievement depended on some things over which governments had no control.

''There's got to be emergency accommodation for people or systems to provide emergency accommodation for people who've got big problems and … we can do all of those things and we must do them better as time goes by,'' he said. ''But we just can't stop people from being homeless if that's their choice or if their situation is such that it is just impossible to look after them under certain circumstances so I would rephrase a commitment like that.''

Mr Abbott was responding to a question by the chief executive of the Sacred Heart Mission, Michael Perusco, who asked whether a Coalition government would continue the Rudd government's pledge to halve homelessness by 2020.

Mr Abbott also surprised some of the people in the room with a biblical reference that some felt was inappropriate. ''You know politicians love to make big heroes of themselves by making these sweeping statements and yet I, who was it who said 'the poor you have with you always?' … you know everyone in the Catholic tradition is trying to build a better world but we know this one is never going to be perfect and that doesn't stop us, doesn't excuse us from trying to do better, but it should caution us against thinking that we are going to achieve heaven on earth. It just can't be done.''