Nicola Sturgeon is to give evidence to MSPs over the cost and delays in the construction of two new CalMac ferries.
The Holyrood public audit committee will face the first minister in a follow up to a damning Audit Scotland report.
The ships could end up costing £300m, and are five years late.
Nicola Sturgeon has assumed responsibility for the issue, saying the 'buck stops' with her.
Jane Barlow
Ms Sturgeon has previously admitted that the "buck stops" with her, despite her transport minister Derek Mackay approving the deal.
The "fixed price" contract amounted to £97m and was awarded to Fergus shipyard in 2015, a year after it was rescued by businessman Jim McColl, an SNP supporter.
The yard going into administration again in 2019 prompted troubles in the construction of the ships, Glen Sannox and the unnamed Hull 802.
The shipyard was later nationalised, but neither ship is yet to be delivered.
An Audit Scotland report in March reported "multiple failings" including the lack of a "full builders guarantee", a key feature of a major shipbuilding contract which covers the buyer if issues arise.
The report is also critical about a lack of record keeping on why the decision was made.
Emails were later published by the Scottish government that confirmed the deal was approved by Derek Mackay, but Ms Sturgeon has assumed responsibility as first minister during Holyrood exchanges.
She said: "The buck stops with me and I have never tried to shy away from that on any issue. I am not defending the cost overruns or the delay to the construction of these ferries, it is completely unacceptable."
Mr Mackay, who left the government in 2020 over messages he sent to a 16-year-old boy, appeared before the public audit committee in September.
He also assumed responsibility, but claimed that some of the financial means had been mitigated by other means.
