If local people want an Integrated Transport Authority for Greater Bristol the government will help them, Mr Cameron said.
The Prime Minister stopped short of openly backing the Evening Post campaign for an ITA – one body that could help bring the area’s transport network into the 21st century – during his visit to the city on Thursday.
But he said if the newly formed West of England Local Enterprise Partnership felt it was right for the area, support was available.
Speaking to the Post, Mr Cameron also said Bristol has a “very strong case” for funding for three major transport schemes.
Three bids for bendy bus routes are due to be submitted to the Department for Transport in September, for a decision in December.
These are the £50 million Ashton Vale to Temple Meads route, the £102 million north fringe to Hengrove package and the £45 million south Bristol link.
Mr Cameron said: “I think it’s for the Local Enterprise Partnership – which I saw working very well together today, local businesses coming together to what’s right for Bristol.
“If they want an ITA the government can help but we should let local people decide.
“The government can provide money for the transport schemes Bristol needs, and I’m aware bids have been submitted.
“We will make a decision on those before the end of the year and Bristol has a very strong case.”
The three Bristol transport schemes will be competing with more than 40 across the country, for a share of a funding pot only begin to pay for half of them.
The Post launched the “Let’s Get Moving” campaign last month, and has received widespread support from residents, businesses, transport campaigners and councillors and MPs from all parties.
That includes one of Mr Cameron’s rising stars, Bristol North West MP Charlotte Leslie, who backed calls for an ITA during a Parliamentary debate in June.