Anas Sarwar said the party still has work to do.
The Scottish Labour leader has said the party is “not complacent” as a poll suggested it is on course to defeat the SNP in Scotland at the next general election for the first time since 2010.
Anas Sarwar said that while he thinks the Scottish Labour Party has momentum, “we’ve still got a hell of a lot of work to do”.
The research for the Sunday Times projects that Scottish Labour would win 26 seats at Westminster, up from one currently.
This would put the party ahead of the SNP, which is predicted to take 21, down from 45 currently.
The Conservatives are projected to take seven and the Liberal Democrats five, adding one extra seat each.
The Panelbase poll has been carried out since the arrest last Sunday of Scotland’s former first minister Nicola Sturgeon, who was released without charge pending further investigation.
The research also found support for the SNP has dropped, with 34% saying they would vote for the party at the next general election, down five points compared with Panelbase’s last poll in March.
This puts it level with Labour, up three points over the same period, while the Conservatives would take 18% and the Liberal Democrats and others 7% each, the poll suggests.
Commenting on the poll, Mr Sarwar told the BBC’s Sunday with Laura Kuenssberg show: “Of course it’s good news, it’s positive news, but we are not complacent, we’ve still got a hell of a lot of work to do to persuade people across Scotland and across the country that the Labour Party is ready to serve and ready to deliver a transformative Labour government.”
Asked whether securing 26 seats was a realistic prospect, he said: “Two years ago when I became the leader we were 32 points behind the SNP and if you’d told me then that two years on we’d be neck and neck with the SNP in the opinion polls I wouldn’t have believed you, I would have believed we’d be close to them, I wouldn’t have believed we’d be neck and neck.
“I think something different is happening in Scotland, I think there is momentum with the Scottish Labour Party, I think there is a mood for change, but as I say I’m not complacent.”
The poll also found Ms Sturgeon has seen her popularity fall by 38 points since research in February to minus 18.
First Minister Humza Yousaf has a rating of minus 12 while Scottish Labour leader Anas Sarwar scored minus 2 and Scottish Conservative leader Douglas Ross minus 34.
The poll also found 44% of those questioned said Scotland should be an independent country, half said it should not, and the remainder did not know.
Scottish Labour deputy leader Jackie Baillie said: “The polls are clear – Labour has ended the SNP’s stranglehold on Scottish politics and is fighting to win seats across the country.
“The people of Scotland know that only Labour can kick the Tories out and deliver the change we need – all the SNP offer is more chaos and sleaze.
“The road to a Labour government runs through Scotland and the next Labour government will deliver for the people of Scotland.”
Panelbase interviewed 1,007 people aged 16 and over in Scotland between June 12 and 15.
SNP depute leader Keith Brown said: “Following a tough few weeks for the party, support for the SNP remains strong – but we will continue to take absolutely nothing for granted and work every day to deliver for the people of Scotland.
“Until the next election, the people-powered SNP campaign will bring that positive message of a fairer, greener and more equal nation to the doorsteps, and will fight relentlessly for every single vote.
“Only the full powers of independence can protect Scotland from the damage of Brexit and the mismanagement of Tory governments Scotland doesn’t vote for.
“The SNP remain the political powerhouse to deliver that change.”