The Oriental Daily News is suing the Apple Daily and its reporters for allegedly inducing ODN's reporters to disclose information about stories.
The Oriental Daily News is also seeking an injunction to restrain its rival from inducing its journalists to reveal information in future.
Oriental Daily Publisher Limited and OPG Human Resources Limited filed a High Court writ on Thursday against Apple Daily Limited and four of its reporters who work in the breaking-news section.
The writ says there were four occasions on which Apple Daily reporters induced Oriental Daily News reporters to reveal details they had obtained at the scene of breaking news.
'The Apple Daily at all material times maintained a reporting team for spontaneous news which was of a smaller scale or size to that of the Oriental Press Group,' it alleges.
'There was a widespread practice on the part of the journalists of the Apple Daily to procure or induce or to attempt to procure or induce the journalists of the Oriental Press Group to disclose information and/or sources of information relating to local news, in particular, spontaneous news.'
The writ also divulged that the Oriental Press Group had a staff handbook issued by OPG.
In the handbook it states: 'Staff must comply with the confidentiality requirements of the company and must not disclose to any outsider any information or source of information relating to such news, or any information which might cause the report of such news obtained by him during the course of his employment.
'Unless with the requisite approval, staff must not communicate with outside journalists (including inquiring, exchanging, verifying any information relating to any news with outside journalists) in order to ensure that such news would be kept in confidence prior to the publication of such news by the Oriental Press Group.'
The writ says the four occasions on which Apple Daily reporters induced Oriental Daily News reporters to leak information took place between October last year and last month. The Oriental Daily News claimed that as a result of the Apple Daily publishing the same or similar articles, the newspaper had suffered a loss to its advertising income and damage to its reputation.