The Coronavirus (Recovery and Reform) (Scotland) Bill would give ministers the ability to respond to public health emergencies in a similar way to legislation passed in the wake of Covid.
This includes imposing lockdown restrictions and restricting access to schools.
However, critics have branded it a "power grab".
Children's Commissioner Bruce Adamson previously warned the powers may not be lawful under the European Convention on Human Rights because they are permanent and not time limited.
Raising this at Holyrood's education, children and young people committee, Conservative MSP Stephen Kerr suggested the legislation "could be taken to court and found to be unlawful".
But Ms Somerville said some of the arguments put forward were based on a "misunderstanding".
She said Holyrood's Presiding Officer Alison Johnstone had expressed her view the legislation was within the legislative competence of the Scottish Parliament.
The education secretary said any regulations "would obviously have to be compatible with ECHR rights".
She said: "Certainly, I do not have a concern at this time, with what I've seen, that we have an issue with the Bill and its ability to pass through Parliament successfully to become an Act on this point."
Ms Somerville added: "I would give the reassurance that we are very, very confident in where we're at at the moment, but we'll continue the conversations with stakeholders on this matter."
She said there were safeguards in the legislation around how the powers could be used, including that they are "necessary and proportionate" and can only apply for a specified period.
Conservative MSP Oliver Mundell later called Ms Somerville "out of touch".
He said: "I would ask why, as a parliamentarian, should I be putting more power into the hands of ministers when they've been so incompetent not just in the pandemic, but over the course of the last ten years?"
Mr Mundell accused SNP ministers of being "more interested in hoarding powers" than using them to help people.
Mr Kerr, the committee convener, accused Ms Somerville of “very poor judgement” after she made reference to a “Boris Johnson approach” to dealing with Covid.