One reviewer has described their sound as "a mash of traditionally jazz and gypsy instruments playing styles that would easily accompany a circus show, but with the passion of a hardcore punk performance". The Barons of Tang are just one of the many innovative ensembles appearing at this year's National Folk Festival in Canberra, who are gradually changing perceptions of ''folk'' music.

Although the National Folk Festival long ago expanded beyond an Anglo-Celtic focus, a perception still lingers that folk music is still about fiddles and grizzled beards. But where Australian folk music was for so long defined by one genre, it has now broadened dramatically over the past two decades as a result of the globalisation of culture.

Many influences, such as blues, reggae, rock, country, gypsy, bluegrass and punk, are now finding their way into the folk mix. In fact, this year's festival features some headline overseas acts performing in styles that some audiences might not associate with folk. These acts include blues legend Woody Mann and alternative country singer/songwriter Lindi Ortega, both from Canada, as well as country soul singer Tift Merritt, from the US.

Julian Cue, bass player with The Barons of Tang, says that all different styles can be thought of as belonging to separate folk traditions. "For us that's influences such as gypsy jazz, klezmer and tango. We just put them into a modern context with a punk ethic and see what happens."

As well as this fusion, some of the most interesting developments in folk have been within traditional genres. The festival this year will showcase the work of many young performers who are adding a contemporary edge to centuries-old styles.

Vocalist/violinist Hannah Pelka-Caven and guitarist Robert Hillman comprise the Australian duo The Raglins, who perform traditional Australian folk songs with a twist. They draw on material in the National Library of Australia's John Meredith folklore collection for at least half of their repertoire.

"We give traditional Australian folk songs new melodies and instrumentation," Pelka-Caven says. "For example, the traditional ballad Jim Jones has a lot of anger in the lyrics but this wasn't reflected in the original, rather jaunty music. We want to modernise these songs and bring them to a new, younger audience.''

Sydney-based band Castlecomer takes its name from a coal mining town in County Kilkenny but its style is anything but traditional Irish folk. "We draw on many older influences and try to make them more current," guitarist and vocalist Bede Kennedy says.

A family band (four of the five members are cousins), Castlecomer gained fans at last year's National Folk Festival with their five-part vocal harmonies and addictive drumbeats supplementing strong lead guitar lines.

"We never intended to be an acoustic band," Kennedy says, "but we like the idea of being able to turn into one if it suits the occasion. However, at big, live events it's better to be louder."

Then there are those directions in folk that are more unconventional, drawing on non-musical elements of the folk tradition. Canberra-based Juliet Moody and Catherine Crowley describe their duo Sparrow-Folk as ''glam folk'' but rely on their training in improvised theatre to supplement their musical skills. A music video of their song Ruin Your Day, satirising criticism of breast-feeding in public, has received nearly 480,000 hits on YouTube.

"We set out to be a musical duo rather than a comedy act," Moody says. After their debut, as just a blackboard gig at the National Folk Festival, they noticed a strong connection with audiences based on humour.

"We enjoy talking to the crowd and being able to include their comments in some of our impromptu material. Although many of our songs are funny there is always a narrative. And, ultimately, I think that's what all folk music has in common - telling a story in song."

In all the attempts to define folk music of this century, that role of storytelling appears again and again. So too, the idea of ''folk'' as the contemporary expression of traditional art forms. And that means the opportunity for audiences to be participants as much as those performing, something with which The Barons of Tang certainly agree.

"Although we're on the outskirts of folk music, we've cut our career playing folk festivals," says Cue. "We get to do the 11pm slot in the weird tent where all the kids turn up, have a dance and go crazy. We're a great opportunity for people to let loose and we love that."

2014 National Folk Festival from April 17 to 21 at Exhibition Park, Canberra. Ticketing inquiries: 6242 5944. Further details: folkfestival.org.au