OzLotto's Web site is jammed by punters trying to avoid lengthy newsagent queues for a chance at tonight's $90 million jackpot.

Some visitors are forced into looping queues as the Web site struggles to deal with the spike in traffic.

The $60 million in tickets sales taken earlier today is expected to double by close of business and may push the jackpot over $100 million, although it won't be confirmed until entries close.

Last week's $59 million first division prize pool attracted a four-fold increase in Web traffic to ozlotteries.com and nswlotteries.com since OzLotto's $20M jackpot on June 2, according to estimates by alexa.com.

The game hit the biggest Division One prize in Australian history after last week's jackpot, which drew nearly $90 million in sales, failed to produce a winner.

Media reports estimate punters have about a one in 45 million chance of winning from a single combination.

The Web site of Lotto tipster Terry Fisher was also brought down by an influx of punters.