Teresa Duffy will tomorrow attempt to add her name to the list of Irish athletes qualified for the Olympic Games in Sydney, with a big performance in the London marathon.

While the illustrious athletes in the race prepare to battle it out for the prize money, Duffy's primary aim will be to dip below the two hours 35 minutes A-qualifying standard for the Games.

Although Catherina McKiernan has already been pre-selected, there is nobody as yet qualified for the Olympic marathon. To that extent, Duffy's progress in her last attempt to make the time will be monitored diligently by the selectors.

The target is not unrealistic for the Belfast athlete who forfeited the chance of qualifying for a place in the world cross-country team to focus on the London event. Now after a spell of warm weather training in the Algarve, she is hoping that the gamble pays off.

Unfortunately, McKiernan is not sufficiently recovered from injury to challenge for a second success in the race, after winning at the first attempt two years ago. Her handlers report that her comeback is on schedule and that she may run in a 15 kilometres road race in Paris at the end of the month.

In the meantime, she is likely to be among the most interested observers of form in tomorrow's race which includes many of those with realistic expectation of making a big input into the Olympic championship.

Among them are the Kenyans, Tegla Loroupe and Joyce Chepchumba, Derartu Tulu (Ethiopia), Lidia Simon (Romania) and the reigning Olympic 10,000metres title holder, Fernanda Ribeiro of Portugal.

Chepchumba has an outstanding record in the race, winning it for a second time last year after finishing second and third on two earlier visits. Yet, her training partner Loroupe is now probably the more feared competitor after some astonishing runs in recent years.

Ribeiro, now in search of new challenges for conquest, will be conceding all the advantages in road racing experience to her rivals and the bigger threat to the Kenyans is likely to emanate from Tula who was quite superb in winning the world cross-country title.

The men's race offers the prospect of a fascinating struggle between the new world record holder, Khalid Khannouchi of Morocco, his compatriot, Abdelkader El Mouazix, who won the race last year, and the Olympic champion at the distance, Josia Thugwane of South Africa.

Khannouchi, hoping to gain American citizenship in time to represent that country at Sydney, will be making his first visit to London and could find it tough going, in competition with some of the race specialists.

One of them is the Portuguese athlete, Antonio Pinto who, in five appearances, has never finished out of the top three. Twice a winner, he now joins with Italy's Stefano Baldinia to present a strong European challenge to the Africans.

Tomorrow's Dublin five-mile Classic road race will once again bring together the top distance runners in the country along with a host of fun-runners. National crosscountry champion Seamas Power from Clare is expected to lead the field along with Noel Berkeley and Peter Matthews of Dundrum South-Dublin. The race starts at St Peter's Road in Walkinstown at 3 p.m. with proceeds going to Our Lady's Hospital for Sick Children in Crumlin.