* To outsource 450 jobs on top of revamp plan - sources
* Bank announced 5,200 job cuts last year
* More job cuts planned across group - sources
* Commerzbank resolved data security problems - COO on intranet (Adds Commerzbank confirms Bafin probe, COO quote on back-office staff)
By Arno Schuetze and Alexander Hübner
FRANKFURT, July 28 (Reuters) - Commerzbank AG, Germany's second-biggest bank, is widening the scope of its cost-cutting programme and plans to shed more than 450 jobs on top of the 5,200 already announced, three people familiar with the matter said.
At a staff meeting last week, Commerzbank's works council representatives said the latest plan targets 350 jobs cuts at the bank's finance department in Frankfurt by 2017 and 100 at sites in Duisburg and Berlin, according to people who attended the meeting.
"There have been signals from the board that there is more to come and that all departments of the group could be hit in the short term," one of the people said.
A Commerzbank spokesman declined to comment.
Commerzbank, which is in the midst of a radical cost-cutting programme - its second in four years - announced plans last year to shed 5,200 of its roughly 45,000 staff.
It has struggled to overhaul itself since receiving an 18 billion euro ($24.2 billion) bailout following a disastrous merger with Dresdner Bank in 2009.
Other banks in Germany have also been trimming their workforce as they restructure their businesses following the financial crisis.
To fill the gap left by the departure of the 450 employees, Commerzbank plans to shift some accounting work to low-cost firms it controls such as Poland-based Ceri and Eastern Germany-based ComTS, the people added.
"Of course, wages there are much lower. But not only do such moves come with significant severance costs, they also create operational risks," one of the people said.
Mark Roach from union ver.di said that the bank needs to be prepared for resistance if it breaks labor contracts.
Chief Operating Officer Frank Annuscheit said the bank had so far made little use of sharing back-office services to lower costs, according an interview posted on Commerzbank's intranet website and seen by Reuters.
"The good old times won't come back, so we better get used to it," Annuscheit said, adding that Commerzbank was planning a second round of talks on the matter with the works council in mid-September.
German daily newspaper Handelsblatt reported earlier on Monday that Commerzbank planned to outsource parts of its finance department.
Separately, Annusheit said that German regulator Bafin has reprimanded Commerzbank over some data security issues after an investigation.
"Main points of criticism have been resolved in the meantime," he said.
Commerzbank is creating 30-40 information technology jobs to address the problems identified by Bafin, one of the people familiar with the matter said.
($1 = 0.7447 Euros) (Editing by Erica Billingham)