Explore Related Suppliers
A Westpac spokesman said on Tuesday staff working in the affected parts of the bank were told last week their jobs would go.
The decision to axe those roles, which supported IT development and systems maintenance, came after a review that started in November 2011.
Those affected would be offered retraining for redeployment into roles in other parts of the bank, if possible, or receive their full benefits and entitlements.
Westpac head of group media relations Paul Marriage said while these were "difficult decisions", they were designed to improve customer service and keep the bank competitive through using the latest technologies.
"We are committed to retaining our core highly skilled technology workforce in Australia," Marriage said on Tuesday.
"But some IT roles can be more efficiently done by external specialists like IBM.
"These providers have operations in Australia and also overseas."
Marriage said these 119 technology jobs, as well as seven positions in the collections area of the bank, were separate to Westpac's announcement in February of plans to cut more than 400 jobs and send up to another 150 offshore as part of a restructure.
Marriage said Westpac had found 1,500 new roles for staff in the past eight months as a result of internal changes.
The job cuts were first raised by the Finance Sector Union (FSU) on Tuesday morning, and national secretary Leon Carter said the decision was completely unjustified.
"The only reason they are losing their jobs is because our most profitable bank thinks it can now get the job done more cheaply offshore," Carter said in a statement.
"Australian bank customers are sick of banks sending jobs offshore, and Australian bank workers are sick of being sacrificed on the altar of profit."
The majority of the jobs would be from Westpac's Sydney CBD and Kogarah sites, as well as a smaller number from Queensland, South Australia and Victoria.
The technology jobs would be gone by July.
Westpac shares closed down 20 cents at $20.56.
Meanwhile, ANZ Banking Group in February said it would axe 1,000 permanent jobs from its 24,000-strong staff by September.