Two British cyclists are on mission, trying to set a world record for being the fastest women to cycle around the world on a tandem bike.

Catherine Dixon and Rachael Marsden - otherwise known as Cat and Raz - began their trip in Oxford, in the UK, and they have cycled thousands of miles already through Europe, Turkey, United States, India, and Australia, just to name a few countries.

They're doing it to raise money for Oxfam and the Motor Neurone Disease Association.

The rules state the pair must travel at least 18,000 miles in total - about 18 times the length of New Zealand, top to bottom.

Cat Dixon tells Logan Church what inspired them to take up the challenge.