The public will have access to 300,000 extra tickets for the London Olympic Games in 2012, organisers have said.
The increase brings the total number of tickets available to eight million, with prices to be revealed this autumn.
"It's critical as many tickets as possible end up (with) the public," said Olympics minister Tessa Jowell.
The London Olympic Organising Committee (Locog) announced a ballot in spring 2011 to allocate 75% of the tickets, while people can now register online.
Locog's online service enables users to receive the latest ticketing news - but there is no guarantee those who register will receive tickets.
By signing up or by calling 0844 847 2012, people will be able to indicate which sports they are interested in.
They will then be among the first to find out when tickets go on sale in 2011 and how to apply, while those registered will also receive updates on major sporting events, test events and London 2012 developments.
Alongside the increase in Olympic tickets, an additional 500,000 tickets to Paralympic events have been made available, bringing that total to two million, meaning 10 million tickets in all will go on sale.
"Watching an Olympic event in your home country is a once in a lifetime experience," said Jowell.
"That's why it's critical that as many tickets as possible end up in the hands of the general public.
"With 10 million tickets going on sale next year people will have even more of a chance to get the ticket that makes their dream come true."
Locog chief Paul Deighton told BBC Radio 5 live: "We are very conscious of making sure tickets are affordable.
"We will announce the prices in autumn this year and we will stick to our commitment to make them affordable and available."
The amount of tickets available has risen from 9.2 million to 10 million due to modelling work at the 2012 venues.
Deighton confirmed there will be no bias towards Londoners or British residents in the distribution of the tickets.
"The ballot in 2011 will, under EU law, be available to everyone across the European Union. The sign-up scheme will only be done in the UK," he said.