Olympics bosses are facing calls to move the mountain biking to Wales
London 2012 Olympics chief Sebastian Coe is expected to face pressure to stage the mountain bike events in south west Wales during a promotional visit.
Lord Coe is due to meet First Minister Rhodri Morgan to discuss Wales' plans to maximise opportunities at the games. Questions about why a new mountain bike course is planned for Essex when Wales already has courses have been asked by Plaid Cymru MP Adam Price.
Another Essex site near the grounds of a castle is currently being looked at.
The London 2012 Organising Committee has been asked to comment.
The location for a new track for Essex is being looked at after an existing course was criticised for not being challenging enough.
During his visit to Cardiff, Lord Coe is also expected to meet Deputy First Minister Ieuan Wyn Jones and Heritage Minister Rhodri Glyn Thomas.
It is understood Mr Morgan will be pressing for the Olympics delivery leaders to bring the mountain biking event to south west Wales.
Alternative venues in Essex are being looked at
Carmarthen East and Dinefwr MP Mr Price raised the issue at the House of Commons question time last week, saying, compared to Essex, Wales had an essential element for mountain bikers - mountains.
The event has to be held within three hours travelling time of the Olympic village.
Mr Price called for the mountain biking event to be held at the "excellent" facilities at Margam, near Port Talbot.
Mountain biking was introduced at the 1996 Atlanta Games and is staged over a 40-50km (25-31m) course for men and 30-40km (18.5-25m) for women.
Dafydd Davies, a trail planning and design consultant, is UK president of the International Mountain Biking Association.
He told BBC Wales: "Wales over the past few years has been a world leader in developing mountain bike trails.
"We already have world-class riding here in Wales and it would be marvellous if we could get the Olympics here.
"The Olympic bid was built around legacy, and what better place to develop a legacy for mountain biking and for the wider community than south Wales?"
Lord Coe will be joined by senior figures from the Olympics 2012 and they will visit the new £32m Cardiff International Pool, which is to be presented with a certificate as a pre-games training camp.
The delegation, including Charles Allen, chair of the London 2012 Nations and Regions Group, is also to meet a Monmouthshire firm that has won a contract for a steel bridge in the Olympic Park.
Lord Coe has already said that as far back as 2004 his team had come under pressure from the International Olympic Committee to site venues closer to London.
An earlier proposed mountain bike course was at Weald country park in Essex, but it was criticised by inspectors from the International Cycling Union (UCI) who said it was not challenging enough.
Olympic organisers are looking at other venues within the county, with the country park next to the 13th Century Hadleigh Castle seen as a frontrunner, if a deal can be agreed with the landowner.
The site near Benfleet stands on a hill overlooking the Thames estuary.