A Cabinet minister has said Sue Gray's report may be redacted for "security" reasons – amid calls for it to be released in full.
Liz Truss, the foreign secretary, said parts of the internal inquiry could be "problematic to publish".
But she stressed: "We have been absolutely clear that we will publish the findings of the report."
The government could have a fight on its hands if it decides to redact the report, with Tory MPs and opposition figures both having said the report should be released in its entirety.
Labour leader Keir Starmer said on Tuesday: "We need to see the report in full and frankly, some of his Cabinet now need to look themselves in the mirror and ask themselves why they’re still supporting this Prime Minister.
“There’s a Metropolitan Police investigation into the goings on in Downing Street. It’s time that some of those Cabinet members spoke out and said we’re not tolerating this any longer.”
And Conservative MP Andrew Bridgen told Channel 4 News that the findings needed to be "unredacted".
“I think the sooner the report comes out now the better, if it is completed, because we can’t sit under this cloud, paralysing the Prime Minister, paralysing the Government," he added.
But speaking on Sky News on Wednesday morning Ms Truss, who is viewed as a leading candidate to succeed Mr Johnson, said Sue Gray had produced an "independent report" and it "it's a matter for Sue Gray when she sends that report, when she's completed her work".
On whether she supported the prime minister's leadership, the foreign secretary added: "He's admitted that mistakes were made and I 100% support him, and want him to continue as Prime Minister."
Boris Johnson get to decide whether or not the report will be released in full, as he commissioned the inquiry.
The probe is into alleged rule breaking on No 10 during lockdown. The Metropolitan Police on Tuesday announced they were also launching a parallel investigation.
The Gray report is expected to be sent to No 10 on Wednesday; it is expected to be released to the public alongside a Commons statement by Mr Johnson either later today, or on Thursday.
