The Department for Work and Pensions (DWP) has spent £1.7m on social media paid content between June 2017 and September 2018.
Justin Tomlinson, minister for family support, housing and child maintenance, revealed the figure, which was paid through media buying agency Carat, in a written answer to Parliament yesterday (23 October)
He said: "We are the biggest government department with a day to day operation on which around 22 million citizens depend.
"However we are conscious that many people who want information won’t be aware of government channels.
"In these instances paying to reach the widest possible audience is both necessary and responsible. This is in line with other government departments."
Mr Tomlinson was replying to a question made by Tulip Siddiq, Labour MP for Hampstead and Kilburn, who also queried other government departments on their spending on promoted content on Twitter, Facebook and Instagram.
The second biggest spender based on the answers provided was the Home Office, which had paid £850,005 since June 2017 on promoted activity on these platforms.
The Department for Transport and its agencies spent £283,646, while the Foreign and Commonwealth Office paid a total of £106,526 in the same period.
On the other hand, HM Treasury has not made any payments to Facebook, Twitter or Instagram.