The MSP was speaking to around 200 party members with fellow leadership hopeful Richard Leonard at the event at Glasgow’s Royal Concert Hall on Wednesday evening, with both men vying to replace Kezia Dugdale.
Earlier in the day Mr Sarwar had denied being “one of the few” in an interview with BBC Scotland after being questioned about a cash-and-carry business, of which he remains a shareholder, and its failure to pay the real living wage to all staff.
He said United Wholesale (Scotland) Ltd did not pay everyone the real living wage of £8.45 an hour because it was “voluntary”.
But he added that a Labour government would make the wage mandatory for all firms.
Glasgow party members who may have wished to press Mr Sarwar on the subject were denied the opportunity at the hustings event. Linda Stewart, chair of the Scottish Executive committee, informed the audience that no questions on “domestic circumstances and financial arrangements” would be heard.
Instead the two candidates spoke about their ambitions to become the next First Minister of Scotland and lead Labour back to power in Holyrood.
Mr Leonard, who yesterday secured an endorsement from the Unite union, claimed that “too many people know what the Scottish Labour is against and not enough people know what we are for” and called for unions to be given a central role in economic planning.
He added: “History shows that it has always been Labour in power, backed and supported by our wider movement that has transformed Scotland before.
“And so I make no apology for saying that the only coalition I want to see is the one between the Labour Party and the trades union movement.”
Mr Sarwar said he was the best candidate to unite the party in Scotland.
He said: “Helping to elect a UK Labour government is not the only job for a Scottish Labour leader – it is also to persuade the people of Scotland that a Scottish Labour Government and a Scottish Labour First Minister matter too.
“Ten years of constitutional obsession has left Scotland a more divided and more unequal nation.”