She confirmed that discussions looked at a bid featuring Cardiff, Swansea, Newport and other areas together but said it was still early days.
One of Cardiff Council's deputy mayors, Marion Drake - who is responsible for regeneration - said the aim was to put forward a bid that was strong enough to bring the accolade to Wales.
She confirmed that discussions looked at a bid featuring Cardiff, Swansea, Newport and other areas together but said it was still early days.
She said the criteria for applications was yet to be published and this would determine the nature of any application.
The move could create thousands of new jobs and bring in millions of pounds.
Councillors met last week to discuss whether they had a better chance of winning the accolade by competing with each other or joining forces.
Swansea's chairman of leisure, Councillor Robert Francis Davies, said: "We will be putting forward a bid as the South Wales Region of Culture.
"We are not a big enough nation to argue among ourselves.
"It has to be co-operation rather than competition because it will give us a much stronger chance."
He said a workshop was being planned for Swansea to bring together bodies such as the Welsh Development Agency, Wales Tourist Board and representatives from all three councils to formulate the bid.
The joint working plan was suggested by former First Secretary Alun Michael in November.
Mr Michael told the National Assembly for Wales that both Swansea and Cardiff were suitable candidates but warned that a contest between the two could be damaging.
It is understood the EU wants a British area to be awarded the title.
'Still feeling benefits'
Glasgow and Dublin have both been past winners.
In 1990, when Glasgow won the title, 5,500 new jobs were created, tourism was boosted, and the city enjoyed an image make-over and an economic net gain of £14m.
Glasgow City Council spokeswoman Lesley Booth said: "For Glasgow the title led to the city repositioning itself from a city which was economically going down the pan."
She said Glasgow was still feeling the benefits.
A spokesman for the Department for Culture, Media and Sport said: "The purpose of the title is not simply to highlight existing cultural excellence but to encourage cities to develop and innovate in the cultural field."