A part-time Woolworths employee and union delegate has slammed the powerful shop workers' union for the deals it does with big business, as the fallout from yesterday's Fair Work decision against Coles widens.

Key points: Woolworths employee raises concerns about union's pay deal with the supermarket

Woolworths employee raises concerns about union's pay deal with the supermarket He accused the union of not providing enough information about the current wage deal

He accused the union of not providing enough information about the current wage deal The commission ruled yesterday that Coles had overvalued some benefits in its EBAs

The Fair Work Commission ruled on Tuesday that a bargaining agreement between Coles and the Shop Distributive and Allied Employees Association (SDA), left thousands of workers worse off than they would be under the award, and was therefore invalid.

Michael Johnstone, who works part time stacking shelves at a Melbourne Woolworths store, has accused the SDA of failing to provide its members with enough information about the current wage deal the union is negotiating with Woolworths, and the previous deal signed in 2012.

Mr Johnstone, who is a delegate with the SDA, said he had calculated that the majority of workers at his store were worse off under the current workplace agreement between the SDA and Woolworths than they would be under the award.

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He said the union failed to inform its members that some would be worse off under the deal because it slashes penalty rates for night time and weekend work.

"Even as a union delegate I didn't even know what our union was fighting for on our behalf," Mr Johnstone said of the 2012 negotiations.

"There was no mention about the costs involved in the agreement, there is no mention about no penalty rates in the evenings, there is no mention that if you work largely weekends and evenings you're going to be financially worse off, and that to me is inexcusable."

Employee accuses union of selling out workers

Woolworths employs approximately 90,000 workers across the country.

Mr Johnstone accused the SDA of selling out retail workers by doing cosy deals with large retail employers like Coles and Woolworths that benefited some employees, but not others.

"The sceptic in me would say 'well they are benefiting from this arrangement'," he said.

"They might have looked at it and said, 'it's too hard and too expensive to organise retail workers so we'll just get cushy with the employer instead and that's the way we will run our show'.

"That should not be allowed, the members of this union should be as outraged as I am as a delegate and a member myself."

Bernie Smith, NSW secretary of the SDA, rejected the suggestion the union was too close to businesses like Coles and Woolworths and told The World Today that workplace conditions in Australia were the envy of the world.

"The reality is that we seek a cooperative brand of unionism," Mr Smith said.

"If you look around the world at the retail industry, which is a very difficult industry to organise, the best-paid retail workers in the world tend to come from either Australia or some of the Scandinavian countries."

Worker's comment 'very premature': SDA union

Mr Smith said that the negotiations with Woolworths still had a long way to run.

"Those negotiations with Woolworths are far from complete, so I think [Mr Johnstone's comments] are very premature comments to be making," he said.

The current agreement between the SDA and Woolworths expired last year, but remains in place until a new deal is approved by Fair Work.

Negotiations around the new agreement were stalled while an appeal over the legality of the Coles workplace agreement was heard by the Fair Work Commission.

Mr Johnstone said a draft version of the new Woolworths deal sent to union delegates in August last year did not reinstate the lost penalty rates.

On Tuesday, the full bench of the Fair Work Commission ruled that the Coles EBA failed what is known as the better off overall test (BOOT) and would be ruled invalid on June 10 unless Coles make changes.

The BOOT dictates that a new workplace agreement must make all workers better off than they would be under the award, which is the legislated minimum rate of pay.

Coles and Woolworths pay deals feature similar provisions

The proposed Woolworths EBA has similar provisions to the Coles workplace agreement, which cut penalty rates in exchange for a rise in the base rate of pay.

The Fair Work Commission found that the compensation offered to Coles workers who relied on penalty rates was insufficient.

The Coles decision looks set to increase the scrutiny the Fair Work Commission gives to similar workplace agreements brought to it in the future.

A spokesperson for Woolworths said the company was seeking to negotiate a new deal that would be approved by the Fair Work Commission.

"The existing, albeit expired, agreement was approved by Fair Work Commission," the spokesperson said.

"It is our intention to negotiate an agreement that will meet the requirements for it to be approved by the Fair Work Commission after our team members have had the chance to vote on it."