Up and away ... on a frog?

A giant jaguar, green gizzmo and frisian frog are just a few of the unusual characters taking to the skies above Hamilton this week at the annual Balloons over Waikato festival.

The five-day festival is the highlight of the Waikato events calendar, treating locals to the spectacular sight of up to 40 hot-air balloons floating above the city.

The first of many colourful displays was to start early this morning, with a mass flight over Hamilton, weather permitting.

The first round of competition is scheduled for later today, allowing balloonists from around the world a chance to demonstrate their skills. Competition continues until Sunday, when the winners of the international and open events will be announced.

On Friday Waikato schools get to join in the fun when the balloonists soar to places such as Pirongia, Tokoroa and Huntly for the Schools' Host a Balloon event.

The festival highlight takes place on Saturday when the balloons light up the night sky in a synchronised display to music. Organisers expect 60,000 people to watch the nightglow show.

This year's balloonists have come from as far as Switzerland and Canada and include award-winning Australian adventure balloonist Chris Dewhirst.

Mr Dewhirst led the team which made the first successful balloon flight over Mt Everest and holds the record for the highest alpine balloon flight.