Arlene Foster has backed calls for a police probe into delays in repaying Covid-19 support payments.
Sinn Féin’s former West Tyrone Assembly member Catherine Kelly became the fourth member of her party to resign over the relief cash.
On Friday, it emerged that Gary Middleton from the DUP had asked police to carry out a criminal investigation into the delayed repayments.
The First Minister told the BBC’s Good Morning Ulster programme: “I think Gary is right to report this to the police.
“The money is not theirs, the money was received in error and therefore it should have been returned.”
She added that public representatives have a “particular duty” to protect public funds.
“It’s up to the police, of course, whether they decide to instigate criminal investigation but I absolutely support my party colleague in the complaint he has made.”
Under the scheme, a £10,000 (€11,000) payment was automatically sent to any firm in receipt of small business rate relief.
The North's Economy Department said 24,700 grants were paid out under the scheme.
Of those, 2 per cent (452) may not have been eligible.
It has recouped 70 and work is under way to recover all ineligible payments.
Ms Kelly tendered her resignation to party leader Mary Lou McDonald on Saturday afternoon.
Ms McDonald acknowledged and apologised “once again” for the “clear failure to immediately reimburse public money”.
Three other party activists, including former Foyle MP Elisha McCallion and officials in Upper Bann and West Tyrone, stepped down.
Meanwhile, Northern Ireland’s schools have reopened with special safety measures following the extended mid-term break.
They include the mandatory wearing of face coverings for post-primary pupils on school transport.
The North's Education Minister Peter Weir has urged parents and carers not to congregate at school gates when dropping off pupils.
