The UUP has called for the next government to take steps to end expenses for Sinn Fein's Westminster abstentionist MPs.
As Sinn Fein's seven MPs do not take their seats, they do not receive the £79,468 a year salary. They are however entitled to expenses.
Upper Bann MLA Doug Beattie said taxpayers must ask "why in this day and age their taxes are going to help fund a political party whose strategy is overseen by a terrorist organisation".
"It is shameful that in 2019 a political party that is directed by a terrorist organisation, responsible for the murder and maiming of thousands of our citizens, actually receives tax payers money to promote their message and the message of their terrorist controllers," he said.
Last week police said there was no change in their 2015 assessment of the relationship between the IRA and Sinn Fein. The organisation report by the Independent Review Commission (IRC) was silent about the continuing influence of republican terror groups, including the Provisional IRA and the INLA.
Sinn Fein MP Mickey Brady rejected the assessment, saying: "The IRA is gone and not coming back".
In the past year, Sinn Fein's MPs claimed almost £120,000 in expenses. The vast bulk of that was spent on office costs such as rent and rates with the rest on accommodation.
Foyle MP Elisha McCallion claimed almost £25,000 - the most of the seven MPs. While West Tyrone's Orfhlaith Begley claimed the least at just over £12,000.
Mr Beattie said if his party was successful in gaining seats in the December General Election, they would raise the matter in the Commons.
“As it stands now, Sinn Fein’s Westminster expenses are paid for by UK taxpayers, in spite of the fact that Sinn Fein MPs refuse to take their seats," he said.
"Just imagine the outcry if a major political party in Great Britain was directed by a terrorist organisation and clear evidence existed to support this.
"Would it be accepted or tolerated? Would people be happy that their money is going towards such a shameful situation?"
He added: "Nobody could have envisaged that 21 years after the Belfast Agreement was signed, that a major terrorist group would still be impacting on the lives of the people of Northern Ireland.
"If the PIRA Army Council gave direction to Sinn Fein to collapse Stormont then they are still killing our citizens as people die on NHS waiting lists."
Sinn Fein has been asked for a comment.
Sinn Fein MPs' 2018/19 expense claims:
Orfhlaith Begley - West Tyrone: £12,249.53
Mickey Brady - Newry and Armagh: £12,715.78
Michelle Gildernew - Fermanagh and South Tyrone: £16,569.37
Chris Hazzard - South Down: £15,388.76
Paul Maskey - West Belfast: £16,596.70
Elisha McCallion - Foyle: £24,954.78
Francie Molloy - Mid Ulster: £21,289.23