Under the terms of the abatement notice, the operating company CVLX is required to investigate the building of a roof over sheep yards and modify the facilities so they are easier to clean.

The EPA also said recent assessments had shown the odour was far worse than suggested when the saleyards were granted an EPA Works Approval.

The environmental regulator's regional manager for the South West, Carolyn Francis, said the order was designed to find a way to solve "ongoing problems".

"Odour from the saleyards is clearly having an effect on the local community. Over nine months to late November, we received 390 pollution reports from nearly 80 different people," Ms Francis said.

In a press release, she said that environment protection officers had undertaken a technical assessment over recent months.

"Our officers confirmed the residents' reports of a strong odour with manure characteristics that was offensive to human beings, and under the Environment Protection Act 1970, that qualifies as pollution."

She said the assessment showed "the type and intensity of the odour in nearby residential areas is far worse than was predicted when the saleyards were first granted an EPA Works Approval."

A response from AAM Investment Group, the company that manages and operates the CVLX facility, said that it was continuing "to improve operational procedures" and had been "investigating ways to reduce potential odour" since its operations at the site began.

AAM managing director Garry Edwards said the company was committed to giving responses to the EPA by the April 20 deadline noted in the abatement notice.

"CVLX is continuing to work with the EPA to ensure improved outcomes for all involved and will be reporting on a range of options expected to reduce the potential risk of odour from the site", he said.

AAM also said it would finalise a revised odour management plan in the new year, and trials would continue into alternate cleaning equipment and procedures.

It is the third time the company has been hit by an EPA pollution abatement notice since the new sale yards opened in October last year.

The first was issued last December, two months after the saleyards went into operation.

The pollution abatement notice required the company to improve its cleaning methods. The EPA said the company had complied with that notice and it was later revoked.

However, residents continued to report odour issues, and a new abatement notice was issued in May this year.

Under the terms of that notice, CVLX had to draft an odour impact assessment by June.

In the 14 months since the saleyards opened, there have been hundreds of complaints made about the odour.

The Central Victorian Livestock Exchange is the biggest sale yard in Victoria. According to its website, 30 per cent of the Victoria's sheep and lamb sales take place through the facility, helping to generate more than $210 million in livestock sales each year.

Earlier this week, the saleyards marked their busiest day of the year so far with more than 60,000 rams and lambs sold.

Councillors and officers discussed the issue at the most recent ordinary council meeting. North ward councillor Daniel Moloney said there was "no way the community should have to put up with the smell".

He added: "I strongly encourage the owners and operators to do a bit more."

The City of Ballarat's manager of strategic planning Lisa Kendal told The Courier on Friday that she understood the residents' concerns.

She said council had engaged an independent company, GHD, to help assess the odour monitoring data and offer council advice on options to mitigate the effect on the community.

"Community has been asking us to assist as best we can, so we are just trying to inform ourselves as best we can to understand what the solutions are."

"We want to advocate on behalf of the community and to explore every avenue possible to resolve the situation."

"We will keep working with the EPA and CVLX to determine what's possible under the regulations."

The move to the current location on Sunraysia Highway was one of the most protracted processes of any large infrastructure project in the region.

A move from the previous Latrobe Street location, where saleyards first started operating in 1864, was first mooted in 2002.

The eventual location was identified more than 12 years ago, but the move met with fierce opposition from local residents. It was given final council approval in 2015.

EDITOR'S NOTE: The wording of the EPA notice suggested that CVLX needed to "further investigate" building a roof over the saleyards rather than a requirement to build them, which was originally reported.

2002: Then Councillor Wayne Rigg questioned the ability of the Latrobe Street saleyards to meet the needs of the expanding livestock-selling sector in Ballarat.

2005: Council named Cardigan and Learmonth as a possible location for the new saleyards.

Following a groundswell of community opposition, Learmonth was then named for a $30 million agri-business hub that included saleyards and an abattoir in 2006.

2007: Councillors pass the responsibility of the saleyards relocation to Sunraysia Avenue, Miners Rest onto the state government.

2012: Miners Rest is named the site of the new saleyards, City Councillor John Philips wants the new Miners Rest saleyard site to get up and running as soon as possible. Work expected to begin in 2014.

2013: Miners Rest residents say the plans have the potential to ruin their township.

In 2014: RLX Investment Company Pty Ltd and Regional Infrastructure Pty Ltd (RIPL) submit the application to relocate the Ballarat saleyard to Miners Rest.

2015: Council officially approves the planning application with a vote of seven-to-two despite significant public push-back.

2017: Works begin on the new saleyards.

2018: First sales are announced for August 17, however the date is pushed back due to poor weather conditions.

October 2018: The first day of sales takes place at the new facility in Miners Rest.

December 2018: First EPA abatement notice issued.

May 2019: Second EPA abatement notice issued, with CVLX required to

December 2019: Third EPA abatement notice issued.

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