A £20m marketing campaign for the computer giant, Oracle, which boasts the company's software is unbreakable is attracting the attention of thousands of hackers intent on proving it wrong.

Hacking attempts on the company's website have increased 10-fold to 30,000 a week during the campaign.

Before the campaign launched, the company's engineers warned the marketing team that hackers would see the ads as an invitation to try and crack their code. But so far, none has been successful.

Mark Jarvis, senior vice-president and chief marketing officer of Oracle, said: "Normally, we get roughly 3,000 attacks a week. Now we're getting 30,000 attacks a week.

"We are not inviting hackers to come and attack our site - they have decided to take it on of their own accord."

Mr Jarvis said the campaign, which aims to show how robust the company's software is, has been the company's most successful marketing effort ever.

Oracle is planning to spend another £49m on the marketing push.

He admitted the ads were boastful but said they were indicative of the company's style: "It's a little brash, a little boastful, a bit challenging. It's so typically Oracle. It's just our style."

But the cocksure style of the ads carries a huge risk: if one of the hackers does triumph, it would make a mockery of the multi-million-pound campaign and turn it into a humiliating PR disaster.