The action will also impact accounts belonging to the deceased.
In a statement given to The Verge, Twitter said on Tuesday that as part of its commitment to serve the public conversation, it is working to clean up inactive accounts to present more accurate, credible information people can trust across the platform.
"Part of this effort is encouraging people to actively log-in and use Twitter when they register an account, as stated in our 'Inactive Accounts Policy'.
"We have begun proactive outreach to many accounts who have not logged into Twitter in over six months to inform them that their accounts may be permanently removed due to prolonged inactivity," said Twitter.
Any account that hasn't signed in for more than six months will receive the Twitter alert before the micro-blogging platform takes the action.
"We do not currently have a way to memorialize someone's Twitter account once they have passed on, but the team is thinking about ways to do this," Twitter spokesperson was quoted as saying.
A BBC reporter first spotted this and posted on Twitter.
"More on Twitter's action on inactive accounts: The company is clawing back accounts that have been inactive for more than *six months*, which is likely a very large number. Inactive user hasn't *logged in*. Seeking clarification on what happens to useful/fun bot accounts," Dave Lee tweeted.
( With inputs from IANS )