A new batch of about 50,000 tickets to events in the Olympic Park are on sale, London 2012 said today.
They include 25,000 hockey tickets plus seats for diving, handball, modern pentathlon, water polo, basketball and the Orbit tower.
The tickets, from contingency stocks, have been confirmed now venue seating plans have been finalised and the hockey draw has been made.
Fans with tickets they do not want can now try to resell them.
Tickets will be validated and released for sale on a sport-by-sport basis. If a ticket is sold, the ticket-holder will get an email and then a refund within 10 working days of the sale. The original ticket should go back to London 2012. If the ticket remains unsold it will be returned to the customer's account, London 2012 said.
Tickets are on sale at http://www.tickets.london2012.com or by phone on 0844 847 2012.
Would-be spectators can only pay with a debit, credit or prepaid card.
Anyone wanting to check for wheelchair spaces should call the same number and speak to the London 2012 Accessibility team.
London 2012's commercial director Chris Townsend said: "This release of tickets gives people a great chance to attend sport in the popular Olympic Park venues. Tickets for further events will follow in due course and we will inform our ticketing database directly.
"For those people who are no longer able to attend, or cannot give their tickets to friends or family, they can now use our resale platform. This will enable people to resell their tickets in a safe and legal way."