The Federal Opposition says the Greens have been "dudded" in the pension deal they have struck with the Government.

Social Services Minister Scott Morrison and Greens leader Richard Di Natale have agreed to a tighter assets test for the age pension.

It will save nearly $2.5 billion dollars over four years, making it the biggest single measure in the 2015 budget.

Senator Di Natale said in securing the agreement, he had convinced the Government to put superannuation back on the agenda.

But Labor said he had been naive, as the Government had made it clear it would stand by its pledge to leave super unchanged.

The deal means around 170,000 pensioners with modest assets will get $30 a fortnight more, but at the top end, there will be losers.

The part pension would cut out for a couple with assets of $823,000 on top of their family home; it is currently $1.1 million.

No more 'wads of cash' for high income earners: Di Natale

Labor's Jenny Macklin said that saving came from 330,000 part-pensioners losing thousands of dollars.

But Senator Di Natale said the deal was fairer.

"It reverses the changes that the Howard Government introduced back in 2007, which we opposed back then," he said.

Jenny Macklin says Australia has one of the most targeted pension systems in the world. ( AAP: Alan Porritt )

"I thought that Labor would support it, to be frank, I was surprised that Labor would be out there defending the Howard sort of legacy — the 2007 largesse the wads of cash being handed out to people on high incomes."

Ms Macklin defended the current system.

"The pension system in Australia is one of the most targeted in the world," she said.

"What's not sustainable in Australia is the large amount of tax concessions for superannuation going to some of the wealthiest people."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 29 seconds 3 m 29 s Listen to Louise Yaxley's AM report. Download 6.4 MB

Senator Di Natale argued he had convinced the Government to put superannuation back on the agenda.

"We also get a broader review into income retirements," he said.

"We think that's really important, we get superannuation back on to the table as part of the tax white paper."

But Ms Macklin said the Greens had been "completely dudded".

"Tony Abbott has said day after day in the Parliament that he is not going to change the tax concessions on superannuation," she said.

"The Greens have sold pensioners out."

Stakeholders fear for middle Australia

Australian Council of Social Service (ACOSS) head Cassandra Goldie suggested the tighter assets test and has welcomed the deal.

"We are particularly pleased that as part of this arrangement, there's a firm commitment from the Government to now specifically look at the superannuation tax concession arrangements," Dr Goldie said.

But Mr Morrison reinforced the Government did not want super to change.

"The Government has made it crystal clear that our policy when it relates to superannuation and particularly taxation and the flexibility of people's arrangements is unchanged," he told the ABC's 7.30 program.

Michael O'Neill from Seniors Australia says he was concerned, especially for single people whose part pensions would cut out with assets of $500,000 on top of the family home, rather than $800,000.

He said it would hit middle Australians.

"We have numerous examples, of teachers for example, who've worked their whole life, [have] now retired at age 65, [have] just over $500,000 in assets excluding the family home," he said.

"She will be outside the proposed new taper rate.

"By the time you take off the value of a car, some household assets ... she will have under $500,000 to invest and will earn about $19,000 or $20,000 per year from that.

"Now that's $3,000 or $4,000 less than the pension, so clearly she's going to be at a disadvantage."