A hung Parliament at Westminster would provide Scotland with the "greatest opportunity", SNP leader Alex Salmond said today.
Scotland's First Minister said the prospect of no one party winning an overall Commons majority was now a "probability".
He argued that, in those circumstances, the SNP, who have set a target of winning 20 seats in the May 6 election, could seek to extract gains for Scotland.
Mr Salmond spoke out at the launch of his party's election manifesto in Glasgow this morning.
It sets out a number of areas where Nationalist MPs would seek to make gains - by, for example, pressing for Holyrood to have greater financial powers.
SNP leaders also want Scotland to be included in the first phase of any future high-speed rail line.
Mr Salmond said the travel chaos caused by the cloud of volcanic ash highlighted the need for this, stating: "As the events of recent days have shown, the Scottish economy cannot rely on domestic air travel alone."
He declared: "A vote for the SNP is a vote for maximising the influence for Scotland."
The party has also been arguing that more SNP MPs could help protect Scotland from the brunt of future spending cuts.
Mr Salmond said: "More Nats will mean less cuts and it means that the things that matter most to the people of Scotland can be protected."
The SNP leader, who is standing down from Westminster at the election, argued that a hung Parliament would be the "best thing for the people across these islands".
He claimed such a scenario could see the scrapping of the Trident nuclear weapons system, saying: "It is likely, in a balanced Parliament, that the Trident missile system will be among the first casualties."
Mr Salmond said a House of Commons where no one party had an overall majority could "help everyone".
He urged voters to consider this when going to the polls, saying: "I think voting for the objective of denying the Labour or Conservative parties an overall majority would be legitimate and proper."
The SNP would not enter a coalition with any of the main UK parties as it had "fundamentally different" objectives, Mr Salmond claimed.
But he said Nationalist MPs would look at issues on a vote-by-vote basis to try to extract gains
Mr Salmond said: "There will be vital votes in a balanced Parliament and we will use that power.
"The more SNP MPs there are, the more influence we will have."
The SNP manifesto calls for further capital spending to be brought forward to boost economic recovery.
The Nationalists are opposed to Labour plans to increase National Insurance contributions next year, claiming this will cost 10,000 jobs in Scotland.
Mr Salmond insisted the "only real way" to tackle the country's budget deficit was by boosting economic growth.
The manifesto also sets out the party's aim of having 60,000 new jobs in the green energy sector over the next decade, along with increased support for former armed forces personnel through the introduction of a veterans card in Scotland - something the SNP administration at Holyrood is looking to do.
Nationalists also want pensions and the minimum wage to rise in line with earnings and for paternity leave to be extended.
The First Minister pledged SNP MPs would "defend the Scottish budget", adding: "We say cut the things that don't matter so you can protect health and education and things that matter."
The Nationalists fear Scotland will suffer cuts no matter which party is voted into power at Westminster, with Mr Salmond vowing his party would "seek to protect the country from the Labour, Tory and Liberal cuts agenda, regardless of whether the cuts come from Tweedledum, Tweedledee or even Tweedledem".
Instead of cuts to public services, the Nationalists want to see Trident axed, the House of Lords and the Scotland Office abolished, and for ID cards to be scrapped.
Mr Salmond said his party's plans provided "an alternative future for our country".
He added: "Running through this manifesto is the SNP vision of a new future for Scotland. A Scotland that is independent, socially just and economically secure."
Political rivals dubbed the First Minister "Alex in Wonderland".
Labour Holyrood leader Iain Gray said: "Alex Salmond's only argument is fundamentally weak.
"His claim that 'more Nats means less cuts' doesn't convince people. A poll from the weekend showed that less than a quarter of Scots believe the claim.
"The truth is that more Nats mean Tory cuts."
He added: "There are two massive credibility gaps in this manifesto - no mention of their economic policy and complete silence on who they want to be prime minister in two weeks' time."
Scottish Liberal Democrat leader Tavish Scott branded the SNP manifesto launch "a true Alex in Wonderland performance".
He said: "Salmond says the deficit can be wished away and Scotland can be insulated from the economic reality.
"That is deeply dishonest and the Scottish people know it."
He also claimed the SNP was "simply too small to matter" at Westminster.
Tory shadow Scottish secretary David Mundell also hit out at the Nationalist manifesto, saying: "Where was the independence word? Where were the coherent economic plans to help Britain out of the recession?"
He added: "Alex Salmond is not taking this British General Election seriously. He is not even standing and he is not coming up with the policies, ideas or vision for the future.
"All he is doing is playing fantasy politics about how an independent Scotland would be immune from the global recession. He is simply living in Scot-la-la-land."Reuse content