The Tour de France may still be almost five months away but preparations have already begun for British sprinter Mark Cavendish who makes his first start in the Tour Colombia on Tuesday.

The 38-year-old Astana rider has delayed his planned retirement by a year to have another crack at the Tour de France in the hope that he can break the record of 34 stage wins which he currently shares with the legendary Belgian Eddy Merckx.

"I always think about the Tour de France," said Cavendish.

"I've always thought about the Tour de France in my whole career. But that doesn't mean you take the rest of the races easy."

The Manx Missile faces a tough six-day race that will require plenty of climbing, especially in stage 5, not something that has figured high on Cavendish's storied CV.

"It's hard to compare when it comes to adaptation because I've never really done altitude before," he said.

"We spent a week in Medellin, which was incredible, and then we came up here to Paipa.

"The only problem was I couldn't breathe for two weeks. But now I understand why the riders from Colombia just play with us when they come down to sea level."

Cavendish, racing in Colombia for the first time, is likely to figure in the bustle of a sprint finish in Tuesday's opening 155-kilometre stage from Paipa to Duitama and the Briton is eager to make an early mark on the new season.

"As a sprinter, you're marked on your wins," said Cavendish who has 162 victories to his name.

"Second, third, fourth or fifth doesn't matter, you're rated by your wins. So it's always important to win.

"And both on a physical and mental point, the motivation you get from victories early in the year can carry you through to July."

Cavendish will be in good company in Colombia alongside former Tour de France winner Egan Bernal and former Vuelta a España and Giro d'Italia champion Nairo Quintana who is returning to competition after missing last season through a doping ban.

This year's Tour de France starts on June 29 in Florence before ending in Nice on July 21.