The SNP are on course to take 57 seats in Scotland in the general election after increasing their lead over Labour to 32%.

A new TNS Scotland poll put support for the SNP ahead of the general election at 54%, up 2%, with Labour on 22%, down 2%.

The Conservatives have 13%, the Liberal Democrats are on 6%, while the Greens and Ukip are both on 2%.

According to a seat projection by ScotlandVotes, the new figure would result in the SNP securing 57 seats in the election, with Labour and the Lib Dems taking one seat each.

The poll, conducted between April 1 and 19, also reveals that over two-thirds (67%) say they are certain to vote.

This is higher than the rest of the UK, where 62% said they would definitely vote in the most recent TNS UK-wide poll.

SNP supporters are most likely to say they are certain to vote, at 82%.

Among those certain to vote, 29% remain undecided.

The survey also asked people for their preferred outcome for the General Election, with over a third (35%) saying they would prefer a Labour government compared with 16% who favour a Conservative administration.

Among SNP supporters, almost half (48%) would prefer a Labour government and a quarter would like to see a Labour-led coalition.

Tom Costley, head of TNS Scotland, said: "Nicola Sturgeon and the SNP appear to be going from strength to strength.

"With more people saying they are definitely going to vote than is the case elsewhere in Britain, it suggests that the Scots are more engaged following the independence referendum.

"It remains to be seen what impact the 29% who claim to be undecided as to which way to vote will have on the total number of Westminster seats gained by the SNP."

SNP campaign director Angus Robertson said: "This poll is yet another welcome indication that the momentum in this campaign continues to be with the SNP - more and more people are putting their trust in the SNP to make Scotland's voice heard at Westminster, end the cuts and stand up for progressive politics across the UK.

"What this poll also indicates is that support for the SNP is coming from people who voted No in the referendum as well as those who voted Yes - as people recognise that a group of SNP MPs will make Scotland stronger at Westminster.

"Backing for Jim Murphy and Labour continues to fall, as his desperate campaign continues to misfire and fails to resonate with people in Scotland.

"While this poll is welcome, we are taking absolutely nothing for granted and will continue to work as hard as we can to win the trust of people across Scotland."

On Sunday, a Panelbase survey for the Sunday Times showed support for the SNP was up by three points to 48%, with just over a quarter (27%) of Scots saying they would vote Labour in the election.

Sixteen per cent said they would vote Conservative, 4% backed the Liberal Democrats, 3% supported Ukip and 2% said they would vote Green.

Labour won 41 seats in Scotland in the 2010 election.