The Opposition Leader has instead doubled-down on his criticism, calling it a "dud deal" that would result in Chinese construction workers being brought in on major projects worth more than $150 million.

Drawing the trade argument directly into the electoral fight for the West Australian seat, which will be decided on September 19, Mr Shorten said employment was the main issue being raised with him by voters, and that anxiety over the implications of the free trade deal was high.

"I've had people come up to me and express their concerns with the China free trade agreement," he said.

"They can't understand why Mr Abbott hasn't chosen to stand up more strongly for Australian jobs."

The comments echoed a line being pushed by unions in an expensive electronic media campaign against the deal.

The government has depicted Mr Shorten as irresponsible, with Prime Minister Tony Abbott dialling up his outrage by branding the campaign against the China deal as "xenophobic" and driven by "racist lies".

While Trade Minister Andrew Robb has repeatedly warned that China could pull out of the deal if Parliament quibbles with labour-market testing provisions — ie by seeking to strengthen and specify legal requirements that Chinese investment projects seek to employ Australians before being allowed to bring in Chinese workers — Mr Shorten suggested this was nonsense.

Labor says the wording of the China deal would not need to be reworked or renegotiated because the relevant provisions dealing with so-called "labour-market testing", could be addressed in the legislation in the Australian Parliament.

"We want to amend the enabling legislation around the trade agreement," Mr Shorten said on the campaign trail in Perth with candidate Matt Keogh.

"Let's face it, just because Tony Abbott gives Australians a proposition and asks Australians to sign a blank cheque, who in their right mind would simply agree with Mr Abbott when he says, just trust me," Mr Shorten said.

Asked for details of Labor's intentions, Mr Shorten said: "Mr Abbott hasn't even put the legislation to the Parliament ... why is it that above $150 million you're not going to require that a company tests to see if there's Australians who can do the job?"

Speaking at the Ringwood Job Access Centre in the marginal Victorian Liberal seat of Deakin, Mr Abbott ramped up the pressure on Mr Shorten, listing the Labor figures now in the government's corner on the free trade deal.

"When it comes to the free trade agreement, Bob Hawke supports it, Bob Carr supports it, Simon Crean supports it, the Premier of Victoria, the Premier of SA, the Premier of Queensland, the Chief Minister of the ACT supports the free trade agreement," he said.

"The only people who are against this export agreement are Bill Shorten and the CFMEU. Now, it's high time that Bill Shorten dumped the CFMEU and got with Bob Hawke, Bob Carr and all the other Labor leaders who know what's good for Australia."

Advocates of the agreement say it will lead to a plethora of jobs and opportunities for Australian businesses as they gain greater access to export markets in a country of 1,4 billion people and an economy of some $10 trillion.

Mr Robb said union claims of loose rules around labour hire were a fallacy because the rules are the same as have been used in other free trade agreements.

"The workplace relations arrangements that underpin this agreement are identical to those that operated for six years under the Labor government. In fact they are the rules that the Labor government brought in," he told News Radio.

Also campaigning in Canning, former Liberal prime minister John Howard, said Mr Shorten should listen to Labor premiers from "left, right, and centre," and approve the China pact instead of doing the bidding of the CFMEU.

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