Labour deputy leadership hopeful Ian Murray said he does not want to see an independent Scottish version of the party.
Mr Murray, the only Scottish Labour MP, said the party in Scotland already had much autonomy.
Asked if Scottish Labour should be responsible for its entire policy position, he said: "Absolutely no."
Labour MSP Monica Lennon has called for Scottish Labour to split from the main UK party to end its "losing streak".
But, speaking on the BBC's Andrew Marr Show, Mr Murray said: "We're a UK party and I think we have to act as a UK party.
"What I would do is make sure that the parties have all the autonomy they require.
"The Scottish Labour Party actually has more autonomy than any other part of the UK Labour Party, but it isn't used.
"Let's use that autonomy, and that takes away any issues around becoming a separate party."
He also insisted that future election campaigns should not be run from London, with more regional decision-making.
"Never again should we go into a general election campaign where it's run by London and others around the country are screaming out for resources and targeting," he said.
"We shouldn't be having seats lost by several hundred (votes) when there are thousands of activists in seats we'll never win."
Mr Murray predicted that voters would return to Labour in Scotland if it could demonstrate it was a realistic alternative to a Conservative government at Westminster.
He was also asked about comments by leadership hopeful Lisa Nandy, who a week ago suggested lessons could be learned from places like Catalonia and Quebec in beating "divisive nationalism" with a "social justice agenda".
The unofficial independence referendum in Catalonia in 2017 was marred by violent clashes, with police using batons and rubber bullets, and First Minister Nicola Sturgeon has said people would be "mortified" by Ms Nandy's comment.
Ms Nandy has since claimed her words were "wilfully distorted into supposed support for a right-wing Spanish government".
Mr Murray said: "It's been spun out of control in terms of what Lisa Nandy said.
"And it goes back to your very first question, the way to defeat nationalism in this country and to keep our UK together, because our UK matters, is to have a progressive centre-left Labour government at Westminster."