Greens leader Bob Brown has launched a no-holds-barred attack on Prime Minister Julia Gillard, accusing her of "unfortunate and gratuitous" insults against the Greens which will "come back to bite her".

Last night Ms Gillard used a speech in Sydney to accuse the Greens - who prop up her minority Government - of not valuing work or family.

In an extraordinary attack on her political partners, she said:"The Greens will never embrace Labor's delight at sharing the values of everyday Australians, in our cities, suburbs, towns and bush, who day after day do the right thing, leading purposeful and dignified lives, driven by love of family and nation."

Hitting back today, Senator Brown accused the Prime Minister of "turning her fire on the very people who support her".

"I think that's an unfortunate and unwarranted and gratuitous insult and it's not becoming of a Prime Minister to be talking in those ways about millions of other Australians."

He said Ms Gillard's comments were "a mistake".

"I'll talk to her about that," Senator Brown warned. "She's wrong."

'Party of protest'

It is the second time the Prime Minister has sought to distance Labor from the Greens, labelling them last week as "extreme".

Delivering the inaugural Gough Whitlam address in Sydney last night, Ms Gillard dismissed the Greens as "a party of protest" with "no tradition of striking the balance required to deliver major reform".

"The differences between Labor and the Greens take many forms but at the bottom of it are two vital ones," Ms Gillard said.

"The Greens wrongly reject the moral imperative to a strong economy.

"The Greens have some worthy ideas and many of their supporters sincerely want a better politics in our country. They have good intentions but fail to understand the centrepiece of our big picture - the people Labor strive to represent need work."

Senator Brown rejected the characterisation.

"It's very, very amiss language by the Prime Minister," he said.

"When she describes one-and-a-half million Australian Greens voters as people who don't have a love of family or of nation, for goodness sake, there's something amiss by that insult coming from the Prime Minister."

He rejected Ms Gillard's claim that the Greens have no moral authority on the economy, citing its support for the stimulus package which "saved the country from recession and the loss of 600,000 jobs".

"It wasn't the Coalition that did that, they opposed it. It was the Greens who stepped up to the mark and saved those jobs and small businesses in Australia," he added.

But he says the public spat will not jeopardise the Greens' support for the Government.

"The question is, will the Prime Minister risk losing my friendship over this? No. I think we've got to be mature enough to have differences and to debate those without getting in to high dudgeon about it," he said.

"The Prime Minister has to live with her statements and I think she's getting poor advice on it."

He said the comments smacked of "product differentiation".

"But it's product damage for Labor and that, of course, is where you can end up if you are not very prudent about the words you use in deliberated public speeches," he said.

"They have to be very measured and you have to measure the consequences and sometimes they can come back to bite you."

Opposition leader Tony Abbott says the Government and Greens have faked the disagreement.

"Well, if they [the Greens] are so extreme, why did she form a Government with them?" he said.

"I think what we're really seeing is just a fake fight, a phoney lover's tiff. The fact is that Labor's in office but the Greens are in power. Julia Gillard might be in the Lodge but Bob Brown is the real Prime Minister of this country."