Alexander revealed the exchange, said to have occurred during negotiations on the controversial 2012 Budget, in an interview with The Independent.
Mr Osborne faced ridicule for what was dubbed the “omnishambles” budget in which he cut the top rate of tax from 50p to 45p and was forced into a series of embarrassing U-turns.
The Budget - the coalition’s third - also contained an announcement to increase the personal allowance to £9,205 in April 2013.
Mr Alexander, who served as Mr Osborne’s deputy for most of the coalition Government, said he would not name the “senior” minister who made the remark.
Mr Alexander, who faces an uphill battle to retain his Commons seat in May, said: “In March 2012 when the economy was still in the very early stages of recovery we wanted to do a very big increase in the personal allowance to put a lot of money back into folk’s pockets.
“The Tories priority at the time was the top rate of tax.
“I remember one meeting with a group of senior Conservatives and one of them - I’m not going to say who - said ‘listen you take care of the workers and we’ll take care of the bosses’.
“That was said across the table in one of the meetings where we were discussing the forward policy of the Government. That really spelt out where their priorities lay.”
Mr Alexander’s comments represent a further escalation in rhetoric from the Liberal Democrats toward their erstwhile coalition partners.
Last month, Mr Alexander told Lib Dem activists he was working against a “heartless” Conservative Party as he enforced Liberal Democrat values.
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