Prime Minister Julia Gillard said on Wednesday that Labor's clear purpose for governance is "to offer the best of opportunities ... and meet the needs of the Australian people."

Ms Gillard is reacting to a new book launched by former Labor MP Lindsay Tanner, who served as finance minister during the Rudd Government, titled 'Politics with Purpose', in which it was suggested modern Labor is "under the sway of politics without purpose."

"And politics without purpose is pointless," Mr Tanner was quoted by the Australian Associated Press (AAP) as saying on Wednesday.

However, Ms Gillard told reporters in New York, where she is attending the annual United Nations general assembly meeting, that her government has been working to take advantage of the Australian prosperity amidst the changes that have attended the Asia-Pacific region.

"I can be very clear about the government's purpose ... (its) purpose is to keep the economy strong, to make sure that not only today, but tomorrow," the prime minister stressed.

In his book, Mr Tanner scored what he termed as reactionary Labor policies, which at best summed up what "have mostly been in response to external political circumstances."

"The unedifying gyrations on climate change and asylum seekers over the past 15 years hardly suggest a clear purpose. The national broadband network was an improvised response to an unexpected situation," Mr Tanner was quoted by Fairfax as saying in his book, which started selling today.

He also lambasted the decision by Labor caucus to replace Kevin Rudd as leader, who he described as actually getting things done despite the complaints on the latter's personality as raised by other key Labor figures.

In an interview with ABC this morning, Mr Tanner called Mr Rudd's ouster as "unjustified ... and an extreme over-reaction to a set of circumstances."

He lamented that the Labor leadership at that time panicked and resorted to misjudgments just to assuage fears that were delivered by the party's plunging poll numbers, specifically those of Mr Rudd's.

The same unjust behaviour was again unleashed February this year when Mr decided to challenge Ms Gillard's leadership, Mr Tanner said. The renewed attacks on the former prime minister, he added, were "massively exaggerated."

And he admitted that he did little to address the concerns as they were emerging two years ago. "In retrospect, should I have done more? Probably yes," Mr Tanner was quoted by AAP as saying.

He left federal politics months after Mr Rudd's departure as prime minister.

Mr Tanner warned too that Labor's record in governance will likely haunt the party in the future and give enough leverage to the Coalition in convincing voters that another Labor government would be a grave mistake.

Labor was fairly successful in maintaining a stable domestic economy despite the financial downturn that hobbled most of the key economies, Mr Tanner conceded.

"But it's difficult to see how they can continue to lay claim to them when they publicly describe the government that presided over them as a dysfunctional shambles," Mr Tanner said.