The Anglican Church wants Australians to have fewer children and has urged the federal government to scrap the baby bonus and cut immigration levels.

The General Synod of the Anglican Church has issued a warning that current rates of population growth are unsustainable and potentially out of step with church doctrine - including the eighth commandment ''thou shall not steal''.

In a significant intervention, the Anglican Public Affairs Commission has also warned concerned Christians that remaining silent ''is little different from supporting further overpopulation and ecological degradation''.

''Out of care for the whole Creation, particularly the poorest of humanity and the life forms who cannot speak for themselves … it is not responsible to stand by and remain silent,'' a discussion paper by the commission warns.

''Unless we take account of the needs of future life on Earth, there is a case that we break the eighth commandment - 'Thou shall not steal'.''

The discussion paper, prepared in March, claims that federal government financial incentives encouraging childbirth should be scrapped and replaced with improved support for parents, such as leave.