All construction work at the Cotter Dam site was stopped on early Tuesday morning by the Construction, Forestry, Mining and Energy Union (CFMEU) over safety concerns.

Members of the union refused to remove their blockade until it is sure that the safety issues are addressed. Dean Hill, ACT branch secretary of CFMEU, said despite police threats to tow workers' vehicles that serve as blockade, they would not remove the cars until they get assurance on the safety of cranes used and worker entitlements would be paid.

S&G Verticon, the operator of the three cranes, liquidated the equipment overnight. With the liquidation, the workers refused to operate the cranes unless they are certain of their insurance cover and guaranteed of entitlements.

The police said by 9 a.m. that they would not tow the vehicles but instead remain in place to keep peace.

Besides the industrial row at Cotter Dam, timber workers in South Australia employed by Carter Holt Harvey struck also on Tuesday for 24 hours due to concerns for 1,000 jobs about to be axed.

Carter Holt Harvey had threatened to cut jobs unless it could negotiate cheaper prices for logs. The striking workers rallied at Mount Gambier to pressure Forestry SA to bring down the prices of logs.

"Our intention is not to hurt industry, our intention is not to hurt Carter Holt Harvey in any way - our whole intention is to send a clear message to the government that we are serious and this is the start of a campaign to achieve what we want, which is job security at the end of the day," ABC quoted union organiser Brad Coates.

In Melbourne, 400 striking union construction workers confronted police officers on Tuesday morning near the blockade of the $250-million Emporium Melbourne construction project. The CFMEU has been picketing the site since Wednesday while police tried to help construction workers who did not join the strike to enter the job site.

Reports said some of the striking workers were dragged from horses by police at the corner of Swanston and Lonsdale streets, and police also used capsicum spray on the strikers.

The Supreme Court of Victoria issued an injunction last week which stopped the union from blocking access to the Grocon site. To go around the court order, CFMEU members stayed on Little Bourke and Lonsdale streets which are the boundaries of the Myer Emporium site.

The strike caused the closure of roads which caused delay to tram commuters and motorists.

While CFMEU State Secretary Bill Oliver denied violent clashes occurred between the strikers and police, former Australian Building and Construction Commission head John Lloyd blamed the alleged violent clashes to the axing of the commission that he led for five years.

He accused unions of not showing much respect for the law and only responding to tough action. He cited the reduction of fine for violation of workplace laws and removal of coercive interviewing powers for probers as removing effective deterrents to bad behaviour in the construction industry.

"Once again, it appears the thuggery, the intimidation and the coercion tactics have returned," The Australian quoted Mr Lloyd.

Fines for workplace violations were cut to $33,000 from $110,000 which is peanuts compared to the deep pockets of the unions. Mr Lloyd cited the $40 million net assets of the CFMEU Victorian branch.

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