This Saturday Iceland holds its parliamentary elections and is likely to become the first nation to vote Pirates into government.

The consequences could affect not only this tiny, eccentric North Atlantic nation, but also the world, through proposals to make Iceland a haven for whistleblowers.

On Thursday opposition parties including the Pirate Party met to plan a four-party, anti-government grand coalition – which on the last pre-election polls would defeat the two-party centre-right governing coalition.

It is a precedent-breaking move by the Pirates, who have been running neck and neck with the governing Independence party for the lead in pre-election polls.

The Pirates said a pre-election coalition pact showed voters which election pledges of each party would be kept and which compromised.

"Voters are entitled to know what their vote will mean," the Pirates said in a statement.

The early election was triggered by a political crisis after prime minister Sigmundur Gunnlaugsson stepped aside when the Panama Papers revealed his family was connected to wealthy offshore funds.

Mass protests led to his resignation and an agreement that an election due next year would be brought forward to this weekend.

Paul Fontaine, news editor of the Reykjavik Grapevine said a four-party coalition would be very unusual.

"Icelanders are allergic to coalitions of more than two parties," he said. "The last time we had a multi-party coalition in government it was called 'the government crisis' but it looks like this is the way it's going."

Iceland's current government is a coalition of the centre-right Independence Party and the centrist Progressive Party.

The latest polls have the Independence Party slightly ahead of the Pirate Party, but the Pirates have been trending upwards while Independence is trending down – and the Progressives have plummeted.

The Left Green have also seen a big upswing.

Pirate MP and 'captain' Birgitta Jonsdottir – who lived for years in Australia – said last week the Pirates would not work with either of the two governing parties.

"These early elections have come about as a result of the corruption revealed to the world by the Panama Papers," she was quoted telling local media.

"Five ministers have been exposed as corrupt since the current government took power. In some of the biggest protests in Icelandic history, the public expressed their desire for change."

Mr Fontaine said Ms Jonsdottir, the de-facto face of the party for several years, would not necessarily be the prime minister even though her party was likely to be the biggest member of the winning coalition.

The prime ministership might instead go to Kartrin Jakobsdottir of the Left Greens, due to a local tradition of giving the prime ministership to the junior member of a coalition.

"That's a choice that would make a lot of sense," he said. "The Pirates are known to be a party of surprises."

There is also precedent for a deal by which coalitions rotate prime ministers mid-term.

Iceland has had mostly right-wing governments – the first left-wing government in Icelandic history governed from 2009 to 20013. But the centre right then returned to power.

"What we are seeing right now, as we are seeing across Europe and North America are great number of voters who have become dissatisfied with establishment left and establishment right," Mr Fontaine said. "That accounts for a large chunk of the support that the Pirate Party has been getting."

The Pirates have pledged to revive a five-year-old draft Constitution which had popular support for elements such as nationalising natural resources, enlarging nature reserves and petition-driven referenda.

"It's very appealing to Icelandic voters across the left and right spectrum," Mr Fontaine said.

They have pushed for Iceland to become a safe haven for whistleblowers – intelligence whistleblowers like Edward Snowden, or corporate whistleblowers.

If so, "Iceland's position being in NATO and the Europe Economic Area could have major implications on a foreign policy level," Mr Fontaine said.

But he said the international perception that the Pirates were radicals or anarchists was inaccurate.

"They are highly reformist but they are not radicals, libertarians or anarchists by a long stretch," he said. "[Jonsdottir] is informed by radical ideas but the party itself is reformist."