Statistics from Public Health Scotland released on Tuesday show some 3,553 people were waiting more than eight hours at emergency departments in the week up to October 9.
The figure rose from 3,427 in the week before.
The number of people who waited half a day at A&E fell slightly from 1,510 – a record high – to 1,506 in the same timescale.
Meanwhile, the total proportion of people seen and subsequently admitted or discharged with the four-hour government target fell slightly from 64.3 per cent to 64.2 per cent – but remained above the record low of 63.5 per cent.
Scottish Tory public health spokeswoman Tess White said the figures were “only getting worse” under health secretary Humza Yousaf, adding: “This is nothing short of a scandal.
“The Scottish Conservatives have repeatedly warned that unless the SNP took immediate action, our A&E departments will be overwhelmed this winter.
“Humza Yousaf’s wafer-thin winter plan has failed to make any sort of dent in the mounting pressures our hospitals are facing.”
Labour deputy leader Jackie Baillie said there was a “humanitarian crisis” in A&E.
“That we are now seeing more people waiting over eight hours for treatment than ever before is a deadly portent of the coming winter," she said.
“Despite the crisis in A&E, the health secretary has gone AWOL and only appears to provide commentary on more disarray this winter due to his inaction.
“Staff are working tirelessly, but they are being left high and dry by this failed health secretary.”
The Scottish Government has said 95 per cent of patients should be seen within the four-hour target, but this has not been met since the early days of the pandemic.
Some 9,187 of the 25,684 attendances at A&E in that week waited longer than four hours, the figures showed.
Responding to the figures, Mr Yousaf said the pressures were “driven” by delays in discharging patients from hospital.
“A&E departments are working under significant pressure and, in common with other healthcare systems across the UK and globally, the pandemic continues to impact performance,” he said.
“Recovery from Covid will not happen overnight, which is why we are continuing to work with boards on a number of measures to reduce pressure this winter.
“We are recruiting 1,000 new NHS staff, including 750 frontline nurses from overseas. Our £50 million urgent and unscheduled care collaborative looks to help improve A&E performance by offering alternative routes to care.
“This includes our out-patient antimicrobial therapy service which allows patients to be treated at home or in the community and has already saved 45,000 bed days.
“The pressures experienced by A&E are driven by delays in discharge elsewhere in our hospitals.
“That’s why a focus of our winter plan is on social care and actions to encourage integration authorities to help alleviate these delays.”
Scottish Lib Dem leader Alex Cole-Hamilton said the Government “would rather create a new crisis for Scotland than deal with the one unfolding before our very eyes in A&E” – referencing the new paper on Scottish independence released by Nicola Sturgeon on Monday.
“Patients and staff alike are being taken for granted,” he said.
“Humza Yousaf is no better than the First Minister. His NHS statement was completely devoid of substance.
“Patients and staff cannot carry on like this.
“The health secretary must drop his opposition to an urgent inquiry into the avoidable deaths linked to the crisis in emergency care.”