The proposed restrictions, expected to come into force by spring next year, will prevent under-16s from accessing platforms including TikTok, Snapchat, Instagram, Facebook, YouTube and X.
Messaging services such as WhatsApp and Signal are expected to be exempt.
Speaking to the BBC, Kendall acknowledged many children would attempt to bypass the restrictions.
She said: "I’ve never thought that the ban will be a complete silver bullet.
"I think it is about providing clarity for parents and children, it will be as much about resetting expectations and social norms for children who are seven, eight, nine, 10, now that they won’t be going on social media until they’re 16."
Kendall insisted the UK's use of "highly effective age-verification measures" would strengthen the policy beyond Australia's existing system.
She said: "But I have no doubt children who are currently on social media, for whom it’s an integral part of their lives, will try and get around the ban, and many will succeed.
"But we do think we need to draw this line in the sand, give greater clarity to parents and greater protections for children."
X owner Elon Musk criticised the move, describing it as censorship.
The trillionaire said: "This censorship law is a wolf in sheep’s clothing. The real goal is to enable the UK government to track everyone.
"They always use defensible excuses for the indefensible."
Meta said it shared the government's goal of protecting teenagers but questioned whether bans would achieve that aim.
A spokesperson said: "Like others, we don’t think bans will achieve this goal.
"As we’ve seen in Australia, bans risk isolating teens from online communities and information, and driving them to unregulated alternatives that lack built-in protections and parental controls."
Meanwhile, the Molly Rose Foundation - set up in memory of 14-year-old Molly Russell, who took her own life in 2017 after watching harmful content online - warned the proposals could prove "unenforceable" and fail to address deeper problems surrounding harmful algorithms and unsafe platform design.
Kendall said Prime Minister Sir Keir Starmer had been persuaded by bereaved families during the consultation process, adding: "Every week you don’t act, another children dies or is at risk of dying or is at risk of serious harm."
