Traffic on Exhibition St was blocked for about an hour, with police out in force as protestors pushed for the company's sale to proceed.

Ballarat Trades Hall secretary Graeme Shearer headed the demonstration in a chant calling for jobs and the protection of 160 livelihoods.

Unions led a delegation of 11 employees into the 45th storey offices of Carson and McLellan, where the reception was civil but fruitless.

Liquidator Craig Crosbie said the protest had achieved nothing as the sale of the company rested in the hands of a specialist barrister, who would ultimately decide the company's fate at a meeting first thing Monday.

The sale of the Ballarat flagship to interested buyer Richard Ince of Norvil Foundry hinges on a legal investigation which will determine whether patented property of US valve giant Lunkenheimer can legally be included in the sale.

Without it the company is worth little.

"Before we're going to be in a position to sell I've got to make sure from a legal perspective that I'm protected," Mr Crosbie said.

However, Australian Workers Union spokesperson Victor Jose said the liquidators were unnecessarily impeding the sale, when professional advice assured its legality.

"We're here because we're very angry and frustrated at the lack of commitment and leadership from the administrators," he said.

"Every day that goes by is another nail in the coffin for John Valves workers."

Mr Shearer said the liquidators' "time wasting" was detrimental to the company's sale and that the unions would continue their campaign of pressure regardless of Monday's outcome.

At the heart of the legal wrangle are the futures of 160 employees..

For seven-year employee, Darren Down a no-sale means a bleak future for his family.

"I would say it's put us in limbo. I have a mortgage (and) two children .. the pair of them have been put on hold because I don't know if the money is going to be there to support them."

Then there's Chris Schiltz, who signed a building contract for his home weeks before the company went into voluntary administration last December.

"I don't know where my next job is going to come from," he said.

"This would never have happened if it had been sold then (at the buyer's first offer) when we still had the chance."