Independent Scotland bad for war on terror: Bishop

Foreign Minister Julie Bishop has warned that Britain could be weakened in the global battle against terrorism if Scottish voters support today's independence vote.

As polls show the ballot to break the 307-year-old union between Scotland and England neck and neck, Ms Bishop has expressed concerns that a break up of Britain could harm international counterterrorism efforts.

And a Yes vote could also force an overhaul of some of Australia's national symbols, including the WA State flag.

Almost 4.3 million Scots will go to the polls today after a near two-year debate on the merits of independence. Polls have narrowed over recent weeks with some pointing to a slim Yes victory.

Ms Bishop said while there was no problem with the referendum itself, the result could have global repercussions in areas such as counterterrorism.

"At this time of global uncertainty we look to the United Kingdom for its steadfast support in counterterrorism and as a beacon of freedom, democracy and a positive force for good in the world," she said.

"While I respect the right to a referendum, I hope that the United Kingdom will not be weakened or diminished as a global power."

Opposition Leader Bill Shorten, who traces family to Scotland, England and Ireland, said though it was a matter for locals he did not back the creation of a new country. "I think the world already has enough borders," he said. "It would be a shame to see new ones being created."

Almost 190,000 West Australians have Scottish family links with about 30,000 of the State's residents born in Scotland.

A Yes vote would also put pressure on the Federal Government - and every State government - to consider changing their flags.

The Union Jack features Scotland's Cross of St Andrew.

AusFlag spokesman Harold Scruby said that if the Union Jack was changed, there would be little choice for Australia but to rethink the national flag.

"We've got about 20 flags in this country, from the Federal flag to all the States and Territories to even fire brigades, that would have to change," he said.

While voting is restricted to people over 16 living in Scotland, Douglas Hutton said the referendum had been a hot topic of debate among his fellow Scots who visit his Joondalup cafe for haggis and black pudding.

Mr Hutton, who migrated to Perth two years ago from Lanarkshire, said there was patriotic sentiment to be independent "but at the same time we've been part of Britain for so long".

He was concerned a slim win or loss would leave a significant number of Scots unhappy and revive religious bigotry between Protestants and Catholics.

"People feel strongly about it," he said. "If it's as close as they say it's going to create ill-feeling."

Mr Hutton favours Scotland remaining part of Britain because of the economic security.

"If they split from Britain now I think it's going to be a financial disaster," he said.

"It's also going to cause a lot of trouble between England and Scotland.

"I think a lot of people are voting with their hearts instead of their heads."