A Cabinet minister has insisted he has "every reason to suppose" the Conservatives properly reported their 2015 general election expenses amid allegations the party breached campaign spending rules.
Communities Secretary Greg Clark claimed investigations into elections were a regular occurrence.
His comments came after Gloucestershire Police launched an investigation into an allegation of electoral fraud relating to the 2015 poll.
The force would not be drawn on which constituency or constituencies the allegation may refer to, or even which party.
But the Conservatives have faced claims that accommodation costs of activists bussed into key constituencies around the country should have been recorded under individual candidates' limits, rather than as part of the national campaign.
Mr Clark told BBC Radio 4's Today programme: "For elections, there are often investigations as to how things have been conducted.
"I have every reason to suppose that the arrangements that we had and all parties had with national battle buses, they get reported in the required way.
"The Electoral Commission oversee these matters, it's right for them to make their own assessment."
The probe launched by Gloucestershire Police comes after the Electoral Commission met with police and prosecutors on Wednesday in a bid to ensure they do not run out of time to launch possible criminal investigations into Tory funding of the 2015 general election campaign.
The Commission believes its ongoing probe into alleged breaches of reporting obligations will take at least another month - potentially taking it past the one-year time limit for launching criminal proceedings.
The claims relating to Conservative spending covering the general election and three parliamentary by-elections were first raised by the Daily Mirror and Channel 4 News.
The party has blamed an "administrative error" for failing to register some accommodation costs.
But David Cameron has insisted it was right to include such expenditure as part of the national campaign.