The number of children at significant risk of exploitation in the city has more than doubled, new figures show.
Trafficking cases across Wales also rose from 34 to 50 in the last year.
But experts say the figures are only the tip of the iceberg - with many cases not officially recorded.
A task force set up by Cardiff council heard from police and many of the 50 different bodies working on the issue.
"The evidence demonstrates that trafficking in Cardiff is increasing, for all types and for all reasons," says its report.
The number of children in the city regarded as being at "significant risk" of sexual exploitation has jumped from 12 to 28 between 2012/2013 and 2013/2104, according to the children's charity Barnardo's.
The council task force found:
The report also points to five court cases in the area in the last three years, including the case in January of a couple jailed for trafficking two Czech women to work as prostitutes.
There was another trafficking case which saw women moved around the UK including to two places in Cardiff.
Cardiff council has been regarded as leading the field in tackling trafficking but it is looking at what more it can do.
This includes raising awareness at spotting signs of trafficking and improving training for staff.
Another concern has been a two-year waiting list for those who have been exploited and need help for post-traumatic stress.
There are also concerns some victims have been offered unsuitable accommodation and qualified social workers have not been available when cases are first referred.
The Black African Women Step Out (Bawso) charity which helps victims of exploitation from ethnic communities, said trafficking has always existed but there is now more awareness from professionals in health and education.
Dr Mwenya Chimba, director of violence against women at Bawso, said: "The problem is very big but the referrals don't reflect the extent of it.
"More recently it's not just the sex trade but forced labour and other forms of exploitation."
Case study - Mary
Mary travelled to the UK from West Africa illegally when she was 14.
She believed she was travelling to a job looking after children in London which would allow her to go to school herself.
But when she arrived in London, after using counterfeit travel documents, she was taken to a house where there were five other girls of various nationalities being forced to work as prostitutes.
She spent a year at the house being made to work as a prostitute and her earnings were confiscated.
Police spotted her during a raid at the house and she was placed in foster care before being referred to the anti-trafficking team.
She was given help and refuge accommodation in Cardiff where it emerged she was pregnant.
She is waiting for a decision to be made on her claim for asylum.
Mary's name has been changed
Yvonne Rodgers, director of Barnardo's Cymru, said closer work between police, councils and the charity had led to more children identified as being at risk of trafficking, more referrals and more protection for victims.
"We need to continue this pattern and see the police authorities in Wales using their full range of law enforcement and disruption tactics to arrest and deter the abusers and protect children from this horrific abuse," she added.
A large number of cases in UK are from countries like Nigeria, Vietnam, China, Albania and Romania.
A council spokesperson said two of its committees had produced a "comprehensive and useful report on this important issue, which takes many forms and which has a profound impact on both children and adults".
It said it looked forward to seeing the recommendations implemented soon.
Human trafficking in Cardiff is increasing year-on-year, with women being exploited for sex and children forced to work, says a new report.