Mr Turnbull said migrants should be required to work first, then draw on social security later.
"They come as skilled migrants and of course they come here on the basis they are going to be employed," he told reporters on Wednesday.
"It's only right they should be working here until they become entitled to that benefit.”
The government has again lengthened the waiting period for migrants trying to access welfare, its second such attempt to extend the wait time in a year.
Back in December, the government announced migrants who arrive in Australia from July will have to wait three years before they can access certain Centrelink payments, extending the current two-year waiting period.
The measure is yet to pass the parliament, but the waiting period will now be extended to four years if the bill comes into law.
The measure is designed to ensure migrants who come to Australia for “economic reasons” know they should be “well-placed to support themselves” when they arrive in Australia, a spokesperson for the Department of Social Services told SBS News.
It will restrict access to key Centrelink payments including Newstart, paid parental leave, the Carers Allowance and the Family Tax Benefit.
Refugees who are found to be fleeing persecution and are given humanitarian visas will still be exempt from any waiting time, as will their families.
Newly arrived migrants who experience sudden financial loss due to a “significant change in circumstances”, including those who fall victim to family violence, will also be granted exemptions, the department said.
Social services groups criticised the measure, slamming it as the harshest changes in the budget, affecting some of the most vulnerable people in the community.
"New migrants lacking paid work ... will be left without income support for the first four years," Australian Council of Social Services CEO Cassandra Goldie said.
"This is not the way to welcome people to this country and help them contribute to its future prosperity."
The measure will save an extra $200 million on top of $1.3 billion in savings announced last year.
Announcing the MYEFO budget update in December, Mr Morrison said the measure would save $1.3 billion over the next four years.
The 2018 Budget layers another $203 million in savings over the coming five years.
The Federation of Ethnic Communities Councils of Australia said the longer waiting times would create "considerable hardship" for migrants.
"We're concerned that puts vulnerable people more at risk," FECCA chair Mary Patetsos told SBS News.