By Shelley Marsden

An Irish runner who is the only man on earth to run seven marathons in less than seven days on seven continents is expected to break his own record today.

Richard Donovan, 45, is on course to complete his final run inSydney.

The father-of-one began his mission inAntarctica, running the first 26-mile leg in minus 20 degrees at the Russian Novo science base last Wednesday.

His current record stands at five days, 10 hours and eight minutes and he has been aiming to knock half a day off that.

If he finishes as planned, his round-the-world marathon will have taken him from Antarcticato Cape Town,South Africa, toSao Paulo,Brazil;Orlando,USA;London,UK; Hong Kong and finally Sydney.

With a deadline of 7pm local time, he will have run 183 miles and flown 27,055 miles.

Running times are independently verified at each location.

Mr Donovan, who was inspired to attempt the challenge in 2009 after the failed bid by British explorer Sir Ranulph Fiennes, said he was not on a special diet, was flying economy on his own and was only bringing what he could fit to one bag.

Money raised through online donations will go to Irish aid agency Goal.