Age UK expects to make up to 90 redundancies by the end of September, the charity said.
In a statement from the charity, Tom Wright, group chief executive of Age UK, said: "We have completed a three-month collective consultation that ended in June 2013 and to date there have been 73 redundancies – 14 of these voluntary. We anticipate this reaching a total of 85 to 90 by the end of September."
Wright said this comprised about three per cent of all staff, from a total workforce of 2,400.
He said Age UK had "implemented a number of changes" because of three factors: fundraising and cost challenges; further integration of support staff following the merger between Age Concern and Help the Aged; and a decision to deliver more services at a local level.
Wright said: "We are committed to avoiding redundancies through redeployment where appropriate. Over the coming year we also plan to create new posts to focus on our priority areas and to support future income growth.
"We are confident that by acting decisively now to make the changes we are planning, we will strengthen our charitable work in the future. It will also equip Age UK to meet the challenges and opportunities that we face as an organisation and those faced by the older people we serve."