Scottish Labour are firmly set for a second place finish at the Holyrood election, a new poll suggests.

The new Panelbase survey, commissioned by the Sunday Times and Heart FM, said that Labour's support in the constituency vote had jumped to 23% - up six points from results by the same pollster in early April.

Meanwhile the Conservatives were on on 17% in the constituency vote, down one percentage point.

Labour have also increased their share of the regional vote to 22% - a four point increase - while Conservative support has remained steady at 19%.

The boost for Kezia Dugdale comes after a week which saw UK Labour mired in controversy over alleged anti-Semitism within the party, while on Wednesday an STV poll suggested her party had fallen to third place.

The poll also suggested that SNP support had slightly fallen in both the constituency and regional votes.

The SNP's share of the constituency vote fell by two points to 49% while the party's support in the regional vote dropped from 47% to 44%.

In the regional vote, the Lib Dems are sitting at 4%, UKIP are on 3%, the Greens are polling at 6%, while new left-wing alliance Rise are up a point to 2%.

The poll was conducted between April 23 and April 28 2016 and surveyed 1074 people.

Crunching the figures into seat predictor Cutbot suggests that were these results to be replicated on May 5, Labour would take 30 seats - down from their total of 37 in 2011 but well ahead of the Conservatives' 23 seats.

It also suggests that the SNP would not increase its majority - it would win 69 seats, identical to its 2011 result. It would only win two of those seats on the regional lists.

Cutbot also indicates that while the Greens would leapfrog the Lib Dems into fourth place, the party would only increase their seats from two to five - compared to some predictions the Greens could take as many as nine.

It also predicts that UKIP would win its first seat, and that the Lib Dems will be reduced to a single seat.

The sole Lib Dem seat would come from a constituency win in Shetland - meaning that party leader Willie Rennie would lose his seat.

But another seat predictor, Scotland Votes, suggests the Lib Dems will hold onto three seats. It also gives the Greens five seats and the Tories 23 seats, but does not predict UKIP will win a seat.

It also predicts Labour will win 27 seats rather than 30, and that the SNP will increase its majority to 71 seats.

Scotland Votes said five of these seats would come from the regional vote.

Polling expert Professor John Curtice, from Strathclyde University, said: "While support for the Conservatives has largely held steady, it looks as though Labour may have been able to capture from the SNP some of those who were thinking of voting for Nicola Sturgeon but who are opposed to independence.

"Certainly the poll is a timely reminder to Ruth Davidson that her party's chances of coming second have always seemed to rest much more on how badly Labour might do rather than how far the Conservatives might advance - and maybe Labour will not do quite so badly after all."

The SNP urged voters to cast both their ballots for the party.

Campaign director and deputy first minister John Swinney said: "Thursday's vote is about who is most able to deliver for everyone who lives and works here.

"Only the SNP has the unity, the ideas and the leadership to keep Scotland moving forward.

"Only by casting both votes SNP can people be sure to re-elect Nicola Sturgeon First Minister."

Scottish Labour said they had a "positive plan" to combat austerity.

A party spokesperson said: "A vote for Labour on Thursday is a vote to ask the richest to pay their fair share so we can stop the cuts to schools and other public services.

"The more Labour MSPs there are in the Scottish Parliament the more voices we have in there fighting against austerity and for using the new powers of that Parliament to invest in our public services.

"If people want change, if they want to stop the cuts so we can invest in the future of our economy then they need to give both their votes to Labour.

"Voting for the SNP and the Tories is a vote for more cuts. Only Labour has a positive plan to stop the cuts and invest in the future."

The Greens said any future MSPs for the party would pursue "bold action".

A spokesperson for the Scottish Greens said: "The trend across recent polls has been positive and our teams of candidates and campaigners are working hard to win every last crucial regional vote.

"Voters tell us they want bold action from what is now a mature Scottish Parliament.

"With a stronger group of Green MSPs, they won't be disappointed."

The Lib Dems said its messages on issues like education and mental health were getting through to the electorate.

Party leader Willie Rennie said: "Everywhere I go, people come up to me to say how pleased they are that our party is campaigning strongly on education and that we are giving mental health the attention it has missed out on for years.

"People are considering voting Liberal Democrat for the first time based on our bold and positive programme for Scotland. We are clearly broadening our support and Liberal Democrats will grow at this election."

Cat Boyd from Rise claimed the Tories didn't "deserve to serve as Scotland's official opposition".

Boyd said: "This poll comes as no surprise. Over the past few days, the Scottish Tories have shown their true colours.

"Ruth Davidson was too busy staging another daft photo-op to send a representative to a hustings on the rights of disabled people. The Tories don't deserve to serve as Scotland's official opposition.

"That said, Labour have no one to blame for their decline but themselves. They have run a fractious, gaffe-prone campaign."

She added: "Electing RISE candidates to Holyrood is the only way to get pro-independence socialists back into office."

UKIP Scotland said Labour were "barely hanging on".

A spokesman said: "Considering Labour is the party of opposition in Westminster while the government go from omni-shambles to omni-shambles, it is highly embarrassing for them that they cannot progress on their performance last time round and are barely hanging on with their finger tips.

"The news that the Tories are not doing as well as they would like us to believe in Scotland comes as no surprise. A few protest votes does not make for a revival and fatal decline has been inevitable for years now.

"The most important issue of sovereignty for Scotland is to leave the EU, and UKIP are confident that when Scots start to experience the benefits of Brexit, they will overwhelmingly decide to stay in the UK and turn their back on Brussels forever."

The Scottish Conservatives have been approached for comment.