The six-week window to buy tickets for the London 2012 Olympic Games closes tonight (Tuesday) at 11:59pm.

The application process opened on March 15, with the 6.6 million tickets, available through www.tickets.london2012.com, allocated by ballot – not on a first-come-first-served basis, meaning there is no disadvantage if you make a last-minute application.

Payment will be taken from all successful applicants between May and June, although those who have been successful will not find out what tickets they will receive until June.

Track cycling tickets, which range between £20 and £325, are expected to be among the most heavily oversubscribed, with the velodrome’s capacity set at just 6,000.

Unsold tickets will go on sale again next year but London 2012 organising committee chairman Paul Deighton has urged fans to apply now to try and avoid disappointment.

“Applications have been steady but at a high level, which is in line with operational expectations – but this week it has hit the roof,” he said.

“Every day we have got a massive number of orders, which is not surprising, because people have taken on board that it’s not a first-come, first-served system. They have sat down with their families to decide what they want. Since last Friday, we have seen a high level go to a really high level.

“Every day is different, but also in the last week we have been getting three or four times the applications above and beyond what was coming in for the previous five weeks – and the sky’s the limit based on the pattern that I am seeing at the moment.”