Natalie Bennett hopes to bounce back from a "car crash" interview when the Green leader addresses what her party is billing as their largest ever conference.

The Greens have seen their membership surge to more than 55,500 and the party is doing well in the national opinion polls.

But they suffered a setback after Bennett had a "car crash" radio interview on the Greens' social housing policy.

The distraction torpedoed the party's general election campaign launch and raised questions about Bennett's leadership.

The Australian born politician will now attempt to get back on track as the party hosts its spring conference in Liverpool.

Bennett is expected to focus on the economy, climate change and the NHS in her speech and will outline how the Greens offer a "message of hope and real change".

The Green leader is also expected to argue that Caroline Lucas' record in the House of Commons shows what "a strong Green group of MPs at Westminster" can achieve in the next Parliament.

Lucas will say that the Greens have the chance to forge a "progressive alliance" with the Scottish National Party (SNP) after the election.

"With the rise of the SNP, and with our own Green surge, we have the chance to forge a new grouping in Parliament. A progressive alliance," the Brighton Pavilion MP will argue.

"Of course, in Scotland and in Wales we'll be fighting hard for our distinctive values and policies. Just as we do against those individual Labour and even Liberal Democrat candidates with whom we have something in common.

"That's the nature of British politics under the first past the post system."

The party will be boosted ahead of the conference, which is expected to attract more than 1,300 attendees, as the most recent opinion poll from YouGov put them on 8% – a significant increase on the Greens' 2010 performance of 1%.

The survey, which was conducted between 4 and 5 March, also put Labour four points ahead of the Tories (35% vs 31%), Ukip on 15% and the Liberal Democrats on 6%.