Downing Street has defended Education Secretary Gillian Keegan after she said some pupils in schools with crumbling concrete preferred temporary classrooms.
Rishi Sunak's spokesman said she was "reflecting a conversation" with children, and had his full confidence.
New figures show 174 schools in England have reinforced autoclaved aerated concrete (Raac).
Temporary classrooms are among the safety measures in place.
Responding to an urgent question in the House of Commons earlier, Ms Keegan said: "I have been to a number of these schools, and in fact at the first school I went to the children were all petitioning me to stay in the portacabin because they actually preferred it to the classroom."
Asked why Mr Sunak still had confidence in Ms Keegan, his spokesman said: "The department that she is leading has worked hard in recent weeks... to make sure that, for the vast, vast majority of children their education is unaffected by this challenge."
Labour's shadow education secretary Bridget Phillipson, meanwhile, said the Raac crisis had been a "colossal shambles".
Officials have been checking hundreds of schools every week.
The number of schools in England affected by crumbling concrete stood at 147 on 30 August, but has increased by 27 as of 14 September.
The government said it would be updating its list every two weeks.
Earlier, education minister Baroness Barran and the Department for Education's permanent secretary, Susan Acland-Hood, told the education select committee:
But they were unable to provide figures for the number of classrooms that have already been delivered.
Despite the increase in cases of confirmed Raac in Tuesday's updated list, more pupils in affected schools have been able to return to full-time face-to-face education since the first list was released.
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