London 2012 organisers have announced that they are releasing another batch of tickets for the Olympic Games.

Additional contingency seats for the athletics, swimming, football, volleyball, table tennis and boxing will go on sale on Friday (June 8) priced between £20 and £720.

A further batch for the previously sold-out Olympic opening and closing ceremonies will also go on sale, though these will start at £995.

Around eight million tickets have been sold for the Olympics and Paralympics, less than two-thirds of the total available, Reuters reports.

More than half a million non-football Olympic seats are still available, while just under half of the Paralympic tickets remain unsold.

Sales of football tickets have also been less than forecast, but organisers Locog remain upbeat.

"With 50 days to go there are still plenty of ways to join in and be part of London 2012. We are at advanced stages of venue planning and these represent the final release of Ceremonies and other sport tickets," said commercial director Chris Townsend.

"Over the next few weeks we will release further tickets for other Olympic sports and keep people informed when tickets are available.

"We are delighted with ticket sales to date, and have sold another one million tickets in the last four weeks, prioritising people who were unsuccessful last time around."

The new tickets will be available on a first come, first served basis through the London 2012 ticketing website from 11am this Friday.