Richard Leonard condemned the company behind Dundeeās waterfront redevelopment and accused Amazon of exploiting its workers in Fife during his speech to Labour conference.
The Scottish Labour leader, who vowed to never sign any new private finance deals, said his mission is to rip up the existing economic system by transferring wealth and power from the rich to the poor.
He singled out the V&A builders BAM Construction for their role in blacklisting, a practice which involves compiling information on workers, such as their political views, to potentially deny them employment.
In a speech in Dundee which focused on his plan to for a more active role for the state in the economy, he promised a ārenaissance in our manufacturing industriesā .
Vowing to redistribute wealth, he told Caird Hall the ārich are only so rich because the poor are so poorā.
āOur partyās mission under my leadership is not simply to secure a fairer distribution of wealth from the existing economic system, it is to fundamentally change the existing economic system,ā he said.
Mr Leonard added: āOur strategy will ensure that we stop once and for all giving millions of pounds of public money in subsidies to exploitative tax-avoiding companies like Amazon down the road in Dunfermline.
āAnd that we stop awarding billions of pounds of public procurement contracts to companiesĀ which donāt pay a living wage which use zero hour contracts and which blacklist workers.
āSo we meet in Dundee and we applaud the redevelopment of the waterfrontĀ but we condemnĀ the use of a blacklisting company to do it.ā
BAM says it does not engage in black-listing, but has admitted ālimited useā of a database of 3,200 workers The Consulting Association.
Amazon says it provides a āsafe and positive workplace with competitive pay and benefits from day oneā.
Mr Leonardās tax plans include raising the top rate of income tax, charging tourists to stay here and a social responsibility levy.
He also wants to tax wealth itself, which could see those in expensive homes having to pay a lump sum.
The speech was delivered to Caird Hall on the second day of the three-day Scottish Labour conference, where at least 1,000 activists are gathering.
Mr Leonard laid out his demand for a review of mental health services in Tayside, as he pledged that Scottish Labour would not sign any new private finance deals.
On Saturday he wrote a column for The Courier, backing calls for a public inquiry into services at the Carseview psychiatric unit.
āDundee has a high level of suicides and it is the biggest killer of young men in the city, which is why today I am backing the campaign for an urgent review of mental health services here in Tayside,ā he said.
He said Tayside is spending millions on two private finance contracts for mental health facilities that is āsimply not delivering for those people who need themā.
āThe Carseview contract for example has another nine years to run and is estimated to cost Ā£3m each year,ā Mr Leonard said.
āThe contract for mental health facilities at the Murray Royal and Stracathro hospitals is expected to pay out Ā£300m over the next twenty five years.
āFrom speaking to campaigners, they agree that thereās no time to lose. This is a matter of life or death.
āSo I pledge today, under my leadershipĀ Scottish Labour will go into the nextĀ Holyrood election Ā committed to signingĀ no new private finance deals.ā
The conference has been dominated by divisions in the party over whether it should back staying in the single market after Brexit.
The leadership has been accused of denying activists a vote on the issue, despite widespread calls for it do so.
“Right now we have on the one hand a Tory Government which wants to turn its back on the single market of the European Union and an SNP Government on the other which wants to turnĀ its back on the single market of the UK, which is worth four times as much to Scotland as the EU.
“It is only the Labour Party which is proposing barrier free access to both.”
Just before his speech – in what is seen as a bid to undermine Mr Leonard’s leadership – his predecessor Kezia Dugdale outlined her demand that Labour backs staying in the free trade area, in which member countries must sign up for free movement of labour, goods, services and money.
At the Scottish Labour for the Single Market fringe event, her ally Ian Murray MP, the former shadow Scottish Secretary, criticised Jeremy Corbyn for his “incredibly disappointing” comments in Dundee on immigration.
Setting out his position on the Brexit deal, Mr Corbyn said a future Labour government “cannot be held back inside or outside the EU … from preventing employers being able to import cheap agency labour, to undercut existing pay and conditions in the name of free market orthodoxy”.
Speaking at a fringe event hosted by the Scottish Labour for the Single Market campaign, Mr Murray said: “I’m disappointed that the Labour party is not making this argument – immigration is good for the United Kingdom and Scotland and we have to be brave enough to stand up and make that point.
“And I was incredibly disappointed to see yesterday that the only person smiling after that passage in Jeremy’s speech would have been Nigel Farage.”