The ease with which Sonia O'Sullivan completed the half-marathon distance at the Great North Run on Sunday raised more than a few questions about what she could be capable of over the marathon. Just 13 weeks after giving birth, O'Sullivan's time of 70 minutes and five seconds left some world-class marathon runners in her wake - suggesting another option for the Sydney Olympics.

The marathon has always been a part of O'Sullivan's long-term ambitions, although she's not quite ready to discover whether or not it could prove to be one of her strongest events. "I don't need to know that yet," she says. "It's not on the last day of the Olympics anyway. If it was then definitely it would be something to consider, but the timetable has made the decision for me."

Unlike previous years, the women's marathon in Sydney takes place three days into the Olympic programme, preventing any possibility of doubling in a track event and the marathon. Her London-based coach Alan Storey also played down speculation about O'Sullivan taking on the marathon in the months ahead as a possible indication of whether she should consider the event in Sydney.

"There's little reason to start running marathons when you're still on top on the track," he said after O'Sullivan's highly impressive fourth place in Newcastle.

Either way, O'Sullivan will return to her training base in Australia at the end of the month after running over a more familiar distance at the Loughrea five-mile road race in Galway next Saturday. "I am looking forward now to a race over five miles, and it should be a bit easier than Sunday. At least I can go out and run hard from the start," said O'Sullivan.

The more significant test facing O'Sullivan in the months ahead is likely to be the World Cross Country in Portugal next March, but for the time being she is only describing that "as an option". Although her long and shortcourse victories in Morocco in 1998 seemed to recover the form and confidence which set up her 5,000 and 10,000 metres double at the European Championships in Budapest later that summer, she's holding back on making any commitments to race either distance at this stage.

"It's one of those stops to consider along the way, but the more immediate plan now is to try and get the Olympic qualifying time for the 10,000 metres in Australia before the end of the year. I've still only run it the one time on the track so I need to go and find out more about what I can run."

The A-standard qualifying mark for Sydney of 32 minutes 30 seconds is unlikely to present a serious challenge for O'Sullivan. She was almost a minute inside that when winning the European title in 31:29.33, her debut over the distance, and she is eyeing a 10,000-metre race in Melbourne at the end of December as the first attempt to achieve the mark.

There may be a slight problem, however, in that BLE have stated that they will only accept qualifying times run between January 1st and July 31st.

O'Sullivan has also deferred a decision on her target event in Sydney. The revised Olympic timetable allows O'Sullivan to attempt a 5,000 and 10,000 metres double, with the 5,000 heats taking place on the opening day of athletics, September 22nd, and the final three days later. There is another rest day before the 10,000 metres heats.

"Right now the 5,000 and 10,000 metres are the two options," she says, "and more than likely it will be one or the other. At this stage I have no idea which because between now and next July it's going to be that same training for both anyway. It's only when you get a little bit closer that you have to decide what you want to concentrate on.

"At the moment, I'm not overly confident about the 10,000 metres, but that's only because I need to run another one to find out a little more about the race. The European Championships was just a matter of keeping up and I never thought about the time or how fast we were actually going."

O'Sullivan plans to remain at her Australian base just north of Melbourne through the winter, returning to Europe before the end of the cross country season.

"If I decide to run the world cross country then I'll probably come back a little earlier and if not, I'll be there until the end of March."

Storey, however, won't be accompanying O'Sullivan to Australia at any stage because of his commitments as director of the London Marathon next April.