Keir Starmer must set out a clear policy agenda to win the next general election, Tony Blair has said.
The former Prime Minister believes the Labour leader has done an "amazing" job to reform the party in the wake of Jeremy Corbyn's leadership.
But voters are still confused about the party's current vision.
“For Labour to win, it has got to have a policy agenda that is absolutely clear," Mr Blair told a conference organised by his own institute.
“Those people have got to be comfortable with a Labour Government,” he said.
"The next election, in my view, will be as much about Labour as it is about the Conservatives, because I think people will think: ‘Yeah, OK, in principle, we should put the Conservatives out.’"
His remarks echoes those made by Andy Burnham, who told the Mirror that Mr Starmer must set out new policies before conference season in September.
The Greater Manchester Mayor said the party is in need of a big vision Brits can get behind, and it must be delivered "now".
Taking a harsher stance, Lord Mandelson said many voters have “no clear idea” who Mr Starmer is.
He told the Spectator the Labour leader is running out of time to sell his agenda.
It comes after Labour triumphed in last week's Wakefield by-election, which has renewed hopes that Mr Starmer is rebuilding in the party's former heartlands.
The Labour leader has ditched Jeremy Corbyn's 2019 manifesto and said the party would be "scratching from scratch".
Speaking at the New Statesman Politics Live event, in London, he distanced himself from previous promises to scrap university tuition fees and his predecessor's vow to hike income tax for some of the highest earners.
“What we’ve done with the last manifesto is put it to one side. We’re starting from scratch. The slate is wiped clean,” he said.
He said Labour was still developing its policy offering for the next general election and would have to "make choices about where we put our money".