There are fears there will be no athletics facility in Cardiff for nearly a year in order for the city's football club stadium plan to go ahead.
The current athletics stadium is due to be demolished
The current Leckwith athletics stadium is due to make way for the new £35m 30,000 seater football stadium.
A new athletics arena was to be built before the old one was demolished but the football club has told the council it will be too costly to wait.
Council leader Rodney Berman said he was "very disappointed" at the news.
Cardiff Amateur Athletics Club said being without a stadium for 11 months was "simply not acceptable".
Cardiff City FC plans to build the football stadium on land at Leckwith, opposite the club's current Ninian Park ground, with a retail development.
The athletics arena would be built nearby.
Mr Berman said he understood the new athletics stadium would be in place before the demolition of the current one.
But he says the football club have informed the council that to wait for a new athletics facility to be built would add millions to the cost of the project.
The council leader said this would leave athletes and other users of Cardiff Athletic Stadium without a home for up to 11 months.
Athletics club Cardiff AAC and the Grange Quins football club are among users of the stadium.
Mr Berman said the council had "repeatedly informed" Cardiff City that a new athletics stadium needs to be built before the football stadium work begins and said the council "is determined that CCFC must find a solution to this."
The new football stadium is planned for land opposite Ninian Park
"I am very disappointed that Cardiff City Football Club is now saying it is not going to be possible to construct a new athletic stadium before the existing one is demolished," said Mr Berman.
"Up until now they had always indicated that this would be possible and this news now places everyone involved in this project in a difficult position.
"I am deeply concerned about the impact this could have on the users of the athletics stadium who up until now have always been promised a seamless transfer."
He said talk of alternative facilities at Uwic or Cwmbran needed to be examined carefully, including whether athletes could get there.
Mr Berman said he was happy to hold meetings to try to find a compromise.
Jeff Kirby, the chairman of Cardiff AAC said: "Not having an athletics stadium in Cardiff for 11 months is simply not acceptable. It's a stadium which is used virtually every day.
"We've been in talks with Cardiff City FC and we have agreed to look at a few options with them. There is talk of us using the facility in Cwmbran but that's too far for us.
"There's also talk of us using the Uwic facilities but their outdoor facility is not really up to scratch although to be fair we haven't really looked at that option properly yet."
It is understood Cardiff City believes keeping the athletics stadium open while another is built could cost the project £10m.
BBC News has asked the club for a response.