The Lothians MSP made her first major speech since taking over as party leader at the weekend and pledged to “shake up” Scotland’s political establishment and “provoke a reaction”.
She called for reform of private school funding and the regulation of businesses and warned that the “left-wing posturing” of the SNP must come to and end.
Ms Dugdale already backs a 50p top rate of tax for the wealthiest, which can only currently be delivered at Westminster.
But she also said it is time to consider hikes when Holyrood gets sweeping new tax-raising powers under the Calman Commission plans which will be introduced in April.
“When those new powers come, that conversation about tax and the balance of tax and how much people pay and who pays what has to be had here in Scotland,” she said in Edinburgh yesterday.
“We’ve not had it in the past. The new powers mean we have to face that conversation.”
She said the challenge now lies with the SNP to set out how it will use the new tax powers after “rhetoric” for the past eight years, according to the 33-year-old.
The basic tax rate will effectively be cut by 10p from April, with Holyrood then responsible for raising it back up to the required level in line with need. But this would mean across the board rises.
A few years down the line, possibly in 2017, Holyrood will gain full control over rates and bands under the Smith Commission powers.
Ms Dugdale added: “As the scale of decision-making in Scotland increases so must the scale of our ambition.
“Everyone in Scottish politics will have to stop complaining about what we can’t do and start talking abut what we can do.
“There can be no more excuses for the perpetuation of inequality and injustice.”
In a wide-ranging speech at Edinburgh College, Ms Dugdale also warned of the “comfortable relationship” developing in between government and civil society based on the SNP’s politics of “identity”.
But trades unions, businesses, academics, charities and campaigners must find a “louder voice” amid concerns that many have been intimidated into silence if they speak out against government.
“There is a powerful new establishment in Scotland,” she added. “It dominates government, public life, both parliaments. It’s premise is that shared identity means shared interest.
“But the interests of the rich and the poor, those sat in the boardroom and those stood on the shopfloor, are not always aligned.”
But Nationalist backbencher Sandra White accused the Labour leader of “SNP-bashing”.
Ms White added: “At a time of unprecedented cuts to Scotland’s budget from the Tories at Westminster, the SNP has taken action to protect the poorest people in our society.”