A Labor senator has accused the government of exposing manufacturing jobs to “unfair trade” arguing the removal of Australian tariffs on steel from China had contributed to the loss of work in the sector.

The New South Wales senator Deb O’Neill also took aim at the Coalition for failing to reform the system that protects local industries from products being “dumped” at low prices and for not living up to its “team Australia” rhetoric.

The sharp criticisms were backed by the Australian Workers’ Union, which called on the government to “wake up” and take a hard line amid what it called “China’s increasingly aggressive and unpredictable behaviour”.

But the government – which is currently seeking dialogue with Beijing after tensions with Australia’s largest trading partner rose to a new high last year – dismissed the calls as “amateur theatre”.

The Morrison government has launched a challenge through the World Trade Organization against China’s imposition of anti-dumping tariffs on Australian barley and has also criticised duties on Australian wine.

O’Neill used a Senate speech to shine attention on Australia’s own anti-dumping actions. She said the Anti-Dumping Commission had experienced funding cuts and its “highly respected” commissioner, Dale Seymour, was effectively being forced out when his term expires at the end of this month.

Australian industry currently faced an “unprecedented threat from dumping”, she contended, with domestic demand for steel becoming “even more vulnerable to cheap, dumped foreign steel”.

O’Neill targeted the industry minister, Karen Andrews, over a decision in 2015 when, as a parliamentary secretary, she “signed several ministerial exemption instruments that removed anti-dumping duties on steel from the People’s Republic of China”.

“This is despite near-universal reporting that China was in fact dumping steel on the market,” O’Neill said on Wednesday.

Guardian Australia has been told that every exemption decision made by the Australian government in 2015 was in line with the recommendations of the independent commissioner.

But O’Neill said the steel producer that ran South Australia’s Whyalla steelworks had gone into administration the following year and its operations were only saved by workers agreeing to large cuts in pay and conditions.

O’Neill said the government had since failed to act on a Senate inquiry report that argued the steel industry would decline without urgent action to address “unfair import competition”.

The Labor senator said the Coalition liked to talk up “team Australia”, but when it came time to put on the jersey for Australian industry, Scott Morrison “hasn’t even shown up for training let alone made it onto the field”.

“At this critical moment when Australian industry requires a responsive trade remedy system and a dedicated minister willing to do everything in the government’s power to defend Australian jobs against unfair trade, we are struck with an industry minister and a prime minister who are paralysed. They have an appalling record. They’re asleep at the wheel, leaving manufacturing jobs as a sitting duck to predatory behaviour,” O’Neill said.

When contacted for a response, Andrews said O’Neill was making “personal attacks underpinned by union talking points” in the context of a Labor preselection fight with fellow NSW senator Kristina Keneally.

“Unlike Deb, I’m more interested in delivering for Australian manufacturers than amateur theatre in the Senate,” Andrews said.

The industry minister said O’Neill was having an “each-way” bet “because in the same breath as she applauds our anti-dumping commission and the commissioner, she is calling on me to override their expert and independent advice”.

Andrews pointed to the government’s $1.5bn modern manufacturing strategy and said the government had always supported “a robust and independent anti-dumping system”.

“Our system is similar to many of our key trading partners and ensures Australian industry can compete on an even playing field, while remaining consistent with our international obligations,” she said.

But the AWU said the government needed to “start getting tough on dumping before we start shedding more of our manufacturing capability”.

The AWU national secretary, Daniel Walton, said Australia needed to “hold the line hard on international anti-dumping rules”.

“China’s increasingly aggressive and unpredictable behaviour means we have to protect and strengthen our sovereign capability,” Walton said.

“The OECD knows China has been engaging in predatory behaviour, but it’s gone virtually unchecked for years under the Liberal government.”

New figures on Wednesday revealed the value of Australian wine exports to all destinations declined by 1% to be worth a total of $2.9bn last year, as Chinese tariffs took their toll on exports to that country.

Wine Australia’s export report showed exports to China fell sharply after Beijing imposed tariffs on Australian products in November. For the entire year to December, Australia exported $1bn of wine to China, representing a 14% decline in the value of those goods.

The chief executive of Wine Australia, Andreas Clark, said the decline in exports to China had been offset by significant growth in European destinations, up 22% to $704m – the highest in a decade.

Last week, members of the Nationals called for protectionist policies as a way of “fighting fire with fire” amid trade tensions with China.

National party backbenchers, led by Matt Canavan, want the government to consider imposing tariffs and expanding subsidies to protect domestic manufacturers, but Liberal backbenchers said it would be against the national interest to abandon free and open trade.

The Australian Industry Group’s chief executive, Innes Willox, said China was “just the latest hook that is being used to support the reintroduction of protectionist policies” but such an approach “would not have the slightest impact on China”.