SA 'crucial' for a Labor win: Dastyari

Labor won't be able to form government unless it picks up at least one seat from the coalition in South Australia, one of its highest profile senators has warned.

The latest Newspoll shows voters are turning away from the major parties, with a record 15 per cent planning to support independent candidates or a micro-party.

Labor senator Sam Dastyari will campaign in Adelaide with Opposition Leader Bill Shorten on Monday afternoon.

"This is a knife-edge election and ... there's no point pussy-footing around this," he told 5AA radio.

"If we don't pick up at least a seat in Adelaide and South Australia and hang on to all our seats, there's no way we'll be able to form government."

The Newspoll of 1867 voters revealed backing for micro-parties and independent candidates jumped by three points in the past fortnight.

That put it at the highest level during a formal election campaign in the poll's 31-year history.

Senator Dastyari blamed the growing independent vote on leadership instability within the two major parties.

"With this huge independent [factor] and obviously we call it the X factor the Xenophon factor, who knows what's going to happen," he said.

"All of a sudden, a seat like Sturt, which you think there's no way [the Liberal's] Christopher Pyne with his immense fundraising ability and his profile, would normally have been in trouble - or even someone as incredibly popular as Kate Ellis in Adelaide."