Enterprise resource planning vendor PeopleSoft is stepping up the legal battle with its unwanted suitor, Oracle, by making additional further claims of unfair trade practices.

The first salvos in this legal battle were filed in June, shortly after Oracle launched a hostile bid for PeopleSoft.

Oracle was accused of unfair business practices, trade libel and interference in customer relationships.

PeopleSoft was furious about Oracle's attempts to interfere with its own bid for rival firm JD Edwards, which had also filed complaints against Oracle which will now be incorporated into Peoplesoft's case.

PeopleSoft now claims to have "extensive new facts" relating to these charges. It alleges that Oracle deliberately misled customers over promises to continue to support PeopleSoft's products.

Oracle said it had not seen the filing, but the charges have not dampened the software giant's enthusiasm for acquiring PeopleSoft.

Jim Finn, Oracle spokesman, said: "It would be inappropriate for us to comment without having seen the filing.

"We were aware they were going to file an amended complaint, so we are not surprised and it does not change our commitment to acquire PeopleSoft."

Parts of PeopleSoft's amended complaint has been filed 'under seal' with the court, meaning it will not be made available in the public domain.