Labor hit by post-budget poll

Prime Minister Kevin Rudd has taken a sharp slide in popularity in a key opinion poll in his stride, saying it is evidence the government is making tough decisions.

The AC Nielsen poll taken after last Tuesday's federal budget shows a 10 per cent drop in Mr Rudd's approval rating to 64 per cent, and a five per cent shift in two party preferred support from Labor to the coalition.

The bad news for Labor followed Saturday's surprise state by-election loss to the Greens in the Labor stronghold of Fremantle in Western Australia.

Another poll released Monday by Essential Research shows a fall in Mr Rudd's approval rating from 71 per cent at the end of March to 62 per cent in the past week.

In Melbourne to announce $4.3 billion in funding for a regional rail express from Werribee to central Melbourne, Mr Rudd said tough decisions were necessary to support jobs and return the budget to surplus.

"Taking hard decisions in the national interest in the middle of a global economic recession is necessary for our country for the long term," Mr Rudd told reporters.

"That is what it is about and we will continue to prosecute these sorts of hard decisions."

Opposition Leader Malcolm Turnbull also played down the polls saying he wasn't troubled by them whether they're going up or down.

"I'm sure it's good for morale but I'm very focused on this debt and deficit," Mr Turnbull told ABC Radio on Monday.

The Nielsen poll found that Labor support fell the most among the over-55s who were unhappy at the decision in last week's budget to raise the pension age by two years to 67 by 2023.

Nielsen research director John Stirton, said while voters did not like the pension age rise most thought the budget was fair.

"A majority of voters thought the budget was fair which suggests that while they might not like it, they're happy to roll with that change," Mr Stirton told Sky News.

But it was the first loss of a WA lower house seat to the Greens, who gained a record 44 per cent of the primary vote, which sparked warnings from veterans on both sides of politics.

Labor parliamentary secretary Bob McMullan said the party would lose more seats to the Greens if it became complacent.

"Nobody ever likes losing a seat, particularly not Fremantle which we've held for such a long time," Mr McMullan told Sky News.

"What we should read into it is no seat is safe forever for anybody, and we all have to be sensitive to the concerns of the voters."

Former treasurer Peter Costello said it showed Labor was in trouble in its heartland, with the Greens polling well in the 2007 election in federal seats held by ministers Anthony Albanese in Grayndler, Tanya Plibersek in Sydney and Lindsay Tanner in Melbourne.

He said Labor had always been strongest in the inner cities which were increasingly populated by the well-off and socially conscious.

"Their outlook is much more pro-Green and I think you are going to see quite a bit of this," Mr Costello said on ABC Radio.

"I think that Labor is now in trouble in its inner city heartland."

Australian Greens leader Bob Brown said the result sent an unmistakable message to Mr Rudd on climate change.

"The message to Kevin Rudd is clear: green up the weak, polluter-friendly climate change bill now before federal parliament or suffer the consequences at next year's election," Senator Brown said in a statement.

But Mr Rudd brushed off the concerns, saying the Fremantle result was a case of democracy in action.

"That's a matter for the good people of Fremantle, and the great thing about democracy is people make their own choices and that's what's occurred over there as well," Mr Rudd told reporters.