Last October, the department acknowledged that a backlog of 9,000 was “unacceptable”, but fresh figures show it has reached 9,517 with claims taking an average of six months to process.
A further 1,500 people who have been refused the payment have been waiting an average of nine months to have their appeals heard.
Sinn Féin’s spokesman on social protection, Aengus Ó Snodaigh, said it was “scandalous that people in dire straights are waiting all that time”.
He said the people waiting have in many cases returned home or given up their work to care for a loved one and are “saving the State a fortune”.
The latest figures from the department show a surge in claims for welfare payments with backlogs of up to 40 weeks in some cases.
More than 7,300 people are waiting to have their claims for the disability payment processed. A further 4,000 people who have been denied the disability allowance are waiting over eight months to have their case heard in a bid to overturn the decision.
Some 7,000 people are waiting to have their application for the family income supplement processed with an average waiting time of 16 weeks for new applicants and 18 weeks for those renewing their claims.
Other claims pending include: n23,000 for the jobseekers allowance with an average waiting time of four weeks;
* 3,668 for the one parent family allowance with an average waiting time of four months.
Those waiting to have appeals for welfare benefits hear include:
* 1,524 who have been refused illness benefit, with an average waiting time of 10 months;
* 12 people who have been refused the blind pension and are waiting an average of 18 weeks to have their appeals heard.
Mr Ó Snodaigh said the payments requiring medical assessment are the ones that involve the longest delays and the department “needs to sort it very quickly”.
The department said it has completed a “major service delivery modernisation project” to reduce backlogs for the carer’s allowance.
It said this focuses on two streams: “One concentrates on dealing with new claim intake and processes these without delay, and the other on the backlog which is ringfenced with a clear and targeted plan for its elimination.”
Then new plan, which started in early September, is being closely monitored and managed, a spokesperson said. “A noted increase in the number of new claims processed has been achieved with claims processed substantially exceeding claim intake in recent months.
“The allocation of available resources to this task continues to be monitored in order that the backlog is eliminated in the shortest possible timeframe,” the spokesperson said.