Independent Radio News has said it will cut the length of its hourly bulletins from three minutes to two when Sky takes over the three-year contract next month.
Sky will also scrap a separate 90-second bulletin, broadcast hourly between 7pm and 6am, which is tailored for stations with younger audiences.
Last November, Sky News Radio won the rights to provide the IRN service - which supplies national and international news to more than 250 radio stations.
ITN, which had held the IRN contract for 16 years, said at the time that it was "clearly very disappointed" to have lost the deal.
In a letter sent to subscribers last week, seen by Press Gazette, IRN confirmed that the switch from ITN to Sky will take place after the 1pm bulletin on Tuesday 3 March.
It said the three-minute hourly news bulletin will be replaced by a two-minute Sky-branded bulletin.
IRN employs 34 journalists. Press Gazette understands that they will all be transferred to Sky under Tupe - the transfer of undertakings and protect of employment law.
Under the new contract with Sky, local radio journalists will be allowed to use audio clips direct from the Sky News and Sky Sports News channels - subject to daily limits.
Sky will also supply three daily money news bulletins, three sports updates and will send text message alerts to journalists when a major story breaks.
A broadcast facility at the Sky studios in Millbank will allow journalists to carry out live interviews with their local MPs.
A number of video news packages will also be made available for stations to use on their websites.
IRN said all the Premier League football games will continued to be covered by reporters at the ground, as now.
IRN launched when commercial radio was born in 1973 and supplies news bulletins, audio clips, scripts and forward planning services to the majority of the UK's commercial radio stations.
Its biggest shareholder is Global Radio, the commercial radio group formed last year from Classic FM parent company GCap Media and LBC owner Chrysalis Radio.