Oracle has added new claims to its ongoing lawsuit against software rival SAP.

Oracle added copyright and breach-of-contract claims to its list of allegations against the German software vendor in an amended complaint filed at the end of last week in the US District Court in San Francisco.

"This case is about corporate theft on a grand scale," Oracle's filings state. Oracle now alleges that SAP violated its copyright by illegally downloading software and support documents. The breach of contract claim alleges that SAP violated the terms of use of Oracle's Customer Connection support website.

The amended complaint had been expected by 18 May, but that deadline was pushed back. It is the latest in a series of legal manoeuvres between the two companies, in their ongoing fight for dominance in the enterprise software market.

SAP plans to respond to Oracle's complaint by 2 July, the company said in a statement. "At that time, SAP will set the record straight regarding Oracle's allegations. SAP is eager to vigorously defend this case," SAP said.

The suit alleges that staff at SAP's TomorrowNow subsidiary pretended to be Oracle customers in order to gain access to the PeopleSoft and JD Edwards customer support website. The lawsuit charges SAP, TomorrowNow and 50 unnamed individuals with violating fraud laws and engaging in unfair competition and civil conspiracy.

The lawsuit came out of the blue two days after Oracle had announced strong third-quarter financial results and claimed its business applications revenue was growing much faster than that of rival and market-share leader SAP. The two companies have long been bitter competitors although they also have customers in common, for instance those running SAP applications on Oracle's databases or middleware.

Oracle said it had discovered the illegal access to Customer Connection after noting periods of unusually heavy download activity from the site in late November and December 2006. The vendor claims to have found more than 10,000 unauthorised downloads of its software and support materials, which it then traced to an internet protocol (IP) address in Texas, an SAP America branch office location and the headquarters of TomorrowNow.

Oracle listed customers whose identities TomorrowNow had allegedly purloined, including Honeywell International, Merck & Co. and OCE-Technologies.

Since filing the original lawsuit, Oracle has not spoken publicly about the legal action. SAP's response has been to decline comment on the lawsuit other than to commit to aggressively defend itself and TomorrowNow against Oracle's claims.

As SAP released its first-quarter fiscal results on 20 April, the company's chief executive Henning Kagermann was in defiant mood about the Oracle lawsuit. "We have no intention to settle; why should we?" he said. "We don't think anything is wrong in our company." Kagermann added that SAP planned to formally respond to Oracle's suit within "the next weeks".

The lawsuit raises a number of issues about the viability of the third-party software maintenance market and common practices within that sector, such as how feasible it is for competitors to provide support for their rivals' offerings. Oracle is also a player in the market, providing support for SAP's older R/3 applications through a partnership with Systime Computers since May 2006.

Some observers suggest that if TomorrowNow staff did download the content from Oracle's site, the issue might have had more to do with a lack of a clear policy from Oracle about which content customers and support specialists were entitled to access and what information was out of bounds.