Unite said it was "furious" at the announcement by the National Australia Group (NAG), which will affect workers in its wealth business in areas including Glasgow and Leeds.
A union has attacked news of 130 job losses by the owners of Clydesdale and Yorkshire Banks, saying those affected would find it tough to get other employment.
The union said employees faced compulsory redundancy and the prospect of finding work in tough local job markets.
National officer Dominic Hook said: "NAG raised the hopes of staff then announced today they no longer have a job. The company invested money to train the staff to meet new regulatory requirements giving them hope for the future.
"Now they have been told that the company has changed its mind and decided to close the business down. This is a cruel decision for workers with years of loyal service.
"We are demanding that the company does everything possible to help find the staff alternative employment within the company or elsewhere in the financial services sector."
The company said: "We can confirm that the financial advice service within our business and private bank will close. This decision has been taken after careful consideration and is part of our commitment to focus our support for customers across our core retail and business banking strengths.
"The service provides financial advice to customers within the business and private bank and includes the sale of investment and protection products. This decision does not impact on any of the advice customers have received or policies they already hold.
"We are providing support for the 130 employees impacted by this change. While there may be some opportunities for redeployment, the overall role reduction of 1,400 announced in April of last year remains unchanged. We are sorry that some information was inadvertently made available yesterday to some staff in relation to this announcement and have apologised to them."
The bank added: "We've always been committed to investing in training and compliance, which means impacted staff are in a stronger position when looking for future career opportunities."