An survey of 1,200 people taken confidentially by political pollsters Newspoll found that almost two-thirds of Australian voters opposed a change to the government's `four pillars' ban on mergers between Australia's big four banks.

The survey results obtained by Reuters showed that 62 per cent were against a change to the ban, while two-thirds of voters in marginal electorates were strongly against a change.

The poll found only 15 per cent supported a change to `fourpillars', while 50 per cent strongly opposed any change in policy that would allow such a merger.

A renewed bout of merger speculation broke out on Thursday when a newspaper reported that NAB executives believed they were ready to launch a bid of up to A$20 billion ($13 billion) for Australia and New Zealand BankingGroup Ltd before Christmas.

ANZ's shares jumped as much as 8.5 per cent on Thursday, dragging the rest of the banking sector and the market in general up behind them.

But, NAB must convince the government, which controls the issuance and conditions of banking licences, to drop its ban before any bid could proceed.

Prime minister John Howard and treasurer Peter Costello have reiterated as recently as Tuesday that the ban will remain in place unless there is much more competition in the small business sector of the market.

But, the decision is firstly a political one, and Howard is seen as sensitive to a rising tide of public discontent in the last two years over bank branch closures, staff layoffs, higher fees and growing bank profits.

The Newspoll survey found that 61 per cent expected higher fees and charges and 60 per cent expected poorer customer service if a big bank merger went ahead.

"The research findings confirm that the political risks are very high for any government or political partywho supports or approves mergers among the big four banks," Newspoll said in a briefing paper with the poll.

The other two major banks in the big four are Commonwealth Bank of Australia and Westpac Banking Corp.

Howard is currently trying to force his plan for a value added consumption tax called a Goods and Services Tax (GST) through the senate, which is controlled by the left-leaning Democrats.

The Democrats have been among the most vocal critics of the banks.

Newspoll said views about bank mergers were very firmly held, "and given the intensity of opinion will be difficult to change quickly."

It also noted the strong opposition among marginal electorates.

Howard's conservative coalition won the October 3 election with fewer votes than the opposition Labor party, but a strong focus on marginal seats helped it win a 12 seat majority in the 148 seat lower house of parliament.

"The political risk of supporting mergers can, therefore, safely be assumed to be very high," Newspoll said.

ANZclosed up eight cents at A$11.08 on Friday.

Elsewhere, ANZ had assembled a team of public relations and investment banking advisers to advise on potential bank merger scenarios, industry sources said.

ANZ had taken on investment banks Deutsche Morgan Grenfelland Goldman Sachs and public relations consultants Gavin Anderson Kortlang as advisers, the sources said.