Channel 5 is understood to be objecting to the new BBC3 plans on the grounds that it will use public money to fund programming already provided by commercial broadcasters, including itself.
BBC3 will have a budget of £90m a year and will only broadcast during peak hours. During the daytime, it will given over to broadcasting programmes aimed at the pre-school children's audience.
The new BBC channel was originally rejected by the Department of Culture, Media and Sport because its programming was believed to be too similar to that already provided by commercial broadcasters such as E4 and Sky One.
The BBC, however, was allowed to resubmit plans to culture secretary Tessa Jowell last month and a public consultation was launched.
The new plans include placing more emphasis on current affairs and news, with a news bulletin on the hour when the channel is live.
Channel 5 is understood to be upset because it has just offered Kirsty Young a £1m-a-year contract to return to the station from rival ITV to anchor its news bulletins. The channel is believed to spend £140m a year on its news output.
"We've always been unhappy about the amount of money the BBC proposes to spend on this peak-time only channel aimed at a commercially attractive audience and we have consistently pointed out that there is nothing unique about the BBC3's proposal to show news on the hour every hour," a spokesman for Channel 5 said.
The DCMS public consultation, which invited views from the public and industry about the BBC's plans for BBC3, will close on Friday.
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