"The events of Christchurch have shown us that internet platforms can be used to spread messages of hate and terror," Attorney-General Christian Porter told parliament on Thursday.
"This bill forms an important part of the Australian government's response to these events."
The legislation was introduced and cleared the Senate on Wednesday night, leaving the government one day to secure its passage through the House of Representatives before next month's election.
Labor's shadow attorney-general Mark Dreyfus told the lower house the opposition would help the government pass the laws, as part of its commitment to bipartisanship on matters of national security.
But he said they are not happy about the "ridiculous timeline" they have had to consider the changes, which the party first saw on Monday afternoon.
"This bill is clumsy and flawed in many respects," he said.
Mr Dreyfus said if Labor wins the next election, it would refer the laws to the powerful intelligence and security parliamentary committee and amend them to deal with any issues.
He said tech giants such as Facebook must do more to deal with violent content on their platforms but that hundreds of smaller companies will also be captured by the bill's "onerous obligations".
The laws might also hamper whistle-blowing activities, he said.
Greens MP Adam Bandt whacked Labor for helping to pass the bill, which he first saw when it was introduced to the Senate at 9.13pm on Wednesday.
"We have a very significant bill that is being rushed through before this parliament rises and Labor is going along with it," he said.
Mr Bandt sought to attach a rider to the bill's passage to automatically send it to the intelligence and security committee before August, but ultimately fell flat.
The Law Council had urged politicians to slam the brakes on the changes and let the committee look at them first.
"Laws formulated as a knee-jerk reaction to a tragic event do not necessarily equate to good legislation and can have myriad unintended consequences," president Arthur Moses said.