With World Cup Football frenzy gripping online users, micro-blogging site Twitter has warned of possible outages due to heavy traffic during the event.

Twitter has been grappling with many site problems in the past week, resulting in outages and poor performance.

"As more people turn to Twitter to see what's happening in the world (or in the World Cup), you may still see the whale when there are unprecedented spikes in traffic," one of the engineers at the micro-blogging site, Jean-Paul Cozzatti, said in a blog.

When the site is down, a whale appears on the Twitter site, generally accompanied by a message requesting users to try after sometime.

During the World Cup tournament, a significant surge in activity on Twitter is expected, according to the blog posted on June 11.

"While we are making every effort to prepare for that surge, the whale may surface," Cozzati noted.

Last week, Twitter experienced several incidences of poor site performance and a high number of errors, which was due to "over-capacity" in one of its internal networks.

Going by estimates, Twitter has over 75 million users worldwide.

To avoid problems in the coming days, the blog said that Twitter has doubled its internal network capacity, apart from re-balancing the traffic to redistribute the load.