The Scottish Tories are to this week push for more time in Holyrood to question Health Secretary Michael Matheson over his near-£11,000 data bill.
Mr Matheson said last week – in an emotional personal statement in Holyrood – the bill was racked up by his teenage sons watching football during a holiday to Morocco at the beginning of this year.
But the revelation came just days after the minister said no one else had used the parliamentary iPad.
The bill, which included a cost of more than £7,000 in a single day, had been caused by using the device as a hotspot to allow internet access on another device.
Mr Matheson and the First Minister both declined to appear on BBC Scotland’s Sunday Show, while Ms Robison reportedly pulled out of the programme.
The Scottish Tories’ chief whip Alexander Burnett will push for a further statement this week, with more time for questions.
Scottish Tory leader Douglas Ross said: “Michael Matheson might have run up this eye-watering bill, but he cannot continue to run away from this scandal.
“He – and the other most senior members of the SNP Government – spent the weekend largely avoiding scrutiny and clearly hoping this scandal will just go away.
“That is wishful thinking when we know that the Health Secretary lied to the press and public over whether this parliamentary device had been used for personal purposes.
“His personal statement last week allowed a severely limited time for questioning. A significant number of questions remain wholly unanswered.
“That is why my party is calling for a substantial amount of parliamentary time to be set aside to allow Michael Matheson to make another statement and for us to be allowed extensive questioning to get answers.”
Mr Ross added that the public had “lost confidence in the Health Secretary”, adding: “Until he resigns, or Humza Yousaf does the right thing and sacks him, my party will continue to use every method possible in Parliament to hold Michael Matheson to account for his lies and lack of answers.”
A spokesman for Mr Matheson said: “Mr Matheson is focused on his responsibilities as Scotland’s Health Secretary ahead of what is expected to be a challenging winter for the health service.
“Today, the Health Secretary is chairing NHS Forth Valley’s annual review, meeting with local NHS staff and members of the public to hear directly about the issues affecting them.
“The Scottish Parliament’s timetable is a matter for the parliamentary bureau – the Conservatives have their own opportunities to bring issues forward.”
Speaking to BBC Radio 4’s Broadcasting House programme on Sunday, the First Minister defended Mr Matheson as a “man of integrity”, and added: “For me, Michael – who I’ve known for well over 15 years – is a man of integrity, honesty.
“He should have handled the situation better, Michael knows that and he’s apologised for that.”
The Health Secretary, Mr Yousaf said, did not mislead him over the issue.