The opposition says the federal government's changes to superannuation are better than nothing but believes there's room for improvement.
The Labor caucus agreed not to block the suite of legislation and allowed it to pass the lower house on Tuesday with the intention of proposing some amendments in the Senate.
One of the key elements of the package is limiting personal after-tax, or non-concessional, super contributions to $100,000 per year - down from $180,000 - from July 1, 2017 but allowing catch-up contributions in certain cases.
Individuals with a super balance of more than $1.6 million will also be ineligible for after-tax contributions.
Shadow treasurer Chris Bowen said he was glad the government had finally acknowledged the need for superannuation tax reform.
"This package is better than nothing," he told parliament.
"What we will do ... is make sensible suggestions about how it can be improved."
One of the amendments it will seek to make in the Senate is reducing the $100,000 cap - originally $500,000 on fund balances back to 2007 - to $75,000.
It also flagged its intention to oppose the government's proposal to enshrine the purpose of super in law.
Treasurer Scott Morrison labelled the suggested amendments as "nonsense" and "not responsible".
Revenue Minister Kelly O'Dwyer said the present system offered little flexibility for those who have multiple jobs and careers over their lifetimes, and others who might take a break from work to look after children or care for an elderly parent.
"Australians are hardworking and aspirational, and the government does not want to put a handbrake on that aspiration when it comes to saving for retirement," she told an Industry Super Australia conference in Canberra.
ACTU secretary Dave Oliver told the conference it has never been more important to safeguard superannuation at a time when wage growth is stagnant and cost of living pressures are increasing for many.
The super system has been carefully planned, built and protected over decades by the Australian union movement.
"This is why we are sounding the alarm on the big banks, who continue to eye the trillions of dollars of retirement savings of Australians like a greedy shark, circling a school of fish," he said.
