More than 200,000 people per hour were trying to register to vote in the build up to the collapse of online systems last night.
Cabinet Office minister Matt Hancock told the House of Commons today that the peak usage of the gov.uk site was three times the previous peak witnessed, of 74,000 per hour, just before the 2015 General Election.
Hancock said that the government is urgently looking into new measures to formally extend voter registration, but reiterated Prime Minister David Cameron's encouragement to people to continue to register today.
"People should register to vote now. Those registrations will be captured by the system, and then we have the legal question of whether those can be included," Hancock said.
However, he declined to set a new deadline for registration, instead promising more detail when the government brings forward legislation.
Hancock was responding to an urgent question from Labour's shadow voter registration minister Gloria De Piero.
De Piero pledged her party's support for rapid action, but she added: “We are no clearer as to how the government plans to make this happen and what the new deadline for registration is.”
Hancock responded: “People should register now – today. And we will bring further information as and when we can."
There are currently no plans to extend today's 17.00 deadline to apply for postal votes, which requires voters to have already registered, Hancock said.
525,000 people were successful in registering to vote yesterday, and 4.5m people have done so over the last three months.