Google's £130m UK tax settlement was "not a glorious moment" for the government, Business Secretary Sajid Javid has acknowledged.
The UK tax authorities' agreement with Google has fuelled a "sense of injustice" that big businesses receive preferential treatment, he said.
His comments come a week after Chancellor George Osborne called the settlement a "major success".
Google said it was in favour of reforms to make international tax clearer.
However, shadow chancellor John McDonnell warned the fallout from the tax row had damaged Google's brand.
"The reputational damage to Google, I think, is immense," he said, and suggested the "saving they have made in tax is not worth the reputation damage they have had".
Mr McDonnell also repeated a call for Google and HMRC to release details of how the agreement was struck.
