THE world's biggest Merino flock ewe competition got under way in the Riverina today.

The prestigious Peppin Shaw Riverina ewe flock competition has drawn 10 pastoral station entrants, showcasing up to 10,000 ewes.

Celebrating 21 years, the competition involves commercial flocks in an area bounded by Wanganella in the south to Mossgiel in the north.

About 100 visitors from Victoria and NSW are touring properties today and tomorrow to see a display of the Riverina's best young flock ewes.

This year's judges are Ian Evans, Australian Wool Innovation, Deniliquin, Cam Munro, Egelabra Merinos, Warren, NSW, and Dale Bruns, Beeac.

Last year's judge, Will Roberts, was unable to make the competition after floods on his Morven property.

Lambing and weaning percentages will be used to determine the overall winner.

Competition president David Rankin said the event enabled Merino breeders to display their sheep in the eye of potential buyers.

Last year's rained-out event was modified to fit around the Hay Sheep Show in June.

The winner was the Gibson family, Croidon, Hay, with principal Robert Gibson taking out the Hazeldean trophy for classer of the winning flock.

Mr Rankin said the Peppin Shaw gave visitors a chance to see a range of environments, ranging from grass to saltbush-blue bush country.

He said this year's competition had drawn a mix of corporate and family owned properties.

"With near record rainfalls for the last year in most areas, all the ewes on display will have excellent growth rates, finally showing producers the full potential of their flock after such a long dry period," Mr Rankin said.

Event secretary Stacey Lugsdin said the event would cover 1000km over the two days.

"We aim to make this a forum for discussion on Merino sheep," Mrs Lugsdin said.

"We have had 21 years of competition, we are having a wonderful season and the sheep look magnificent.

Mrs Lugsdin said regional wool growers were rebuilding flocks after numbers were decimated by drought.

"It is the hard core Merino breeders left in the region now," she said.

"During the 1980s and 1990s we used to see more than 10,000 ewes over three days but many of those family farms have sold out to corporates, and introduced other breeds.

"There are now Merino sheep offering ease of management and smooth skin, so those numbers will build again."

Hillston entrant Andrew Peters entered his 2010-drop Ballatherie blood flock ewes in the Peppin-Shaw this year.

His family last entered in 2010 and has since switched the flock from an annual to six monthly shearing.

"It is good to have a look around at other people's sheep and get some feedback to fine tune what we are doing," Mr Peters said.

"We have had 33mm of rain so far this year - I'm quite enjoying this so called climate change.

"This country is as good as you will ever see it."