Sinn Fein MLA Catherine Kelly has become the fourth party member to resign over the coronavirus small business grants controversy.
The party confirmed the news in a statement issued on Saturday afternoon.
Three activists resigned when it emerged there was a delay in repaying unsolicited £10,000 grants that were wrongly paid into party accounts.
The three that resigned previously were former Foyle MP Elisha McCallion as well as officials in Upper Bann and West Tyrone.
Party President Mary Lou McDonald said on Saturday: "This afternoon I accepted the resignation of Catherine Kelly, MLA for West Tyrone. Catherine is a signatory to an account into which a small business grant of £10,000 was lodged in error.
"The grant was unsolicited and has been repaid in full. The failure to return the grant immediately is unacceptable. Catherine fully accepts that she did not discharge her duties as a public representative in this regard.
“The incorrect lodgement of small business grants into three Sinn Fein accounts came to the attention of the Sinn Féin leadership over the course of Monday and Tuesday last.
"The party’s examination of this matter is now complete. As leader, I once again acknowledge and apologise for the clear failure to immediately reimburse public money."
In a statement released through Sinn Fein, Catherine Kelly apologised "unreservedly to the party" and to the "wider public".
She said: "Last week the party correctly intervened in relation to the failure to immediately return money that had incorrectly been paid into a party account in West Tyrone.
"I have been a signatory to that account for a number of years and as such had a responsibility to ensure it was operated to the highest standard. That did not happen in this case.
"I believe that as a public representative this is not acceptable and therefore I have tendered my resignation as a member of the Assembly with immediate effect.
"I apologise unreservedly to the party, to those who vote for us and to the wider public."
