Liberal Democrat leader Sir Vince Cable has said his party has "nothing to apologise for" after questions were raised about election campaign spending.
Edinburgh West MP Christine Jardine is the second in the party to face queries over their expenses in two days, following questions levelled at deputy party leader Jo Swinson.
Reports in The Herald newspaper have claimed both dropped thousands from their election spending returns as the cash was allocated to national rather than local spending, bringing them in under legal caps on expenditure.
Speaking in Edinburgh, Sir Vince said: "My understanding is it's absolutely completely above reproach, that there's absolutely no question of any impropriety and what's happened is it's a complex process apportioning costs, but the party has followed advice.
"There's no question of anything wrong whatsoever, nothing to apologise for.
"As far as I'm aware no official complaints have been made and from what I understand there's no basis for making them."
He claimed the election spending issue affecting his party also impacted on all other political parties.
The Herald claimed Ms Jardine, a former journalist, allocated a third of her election material bill to national spending, because it promoted the Lib Dems rather than her specifically as the local candidate.
It means she would have been £1,350 over the legal spending cap if this £3,000 had been counted towards her constituency campaign costs, according to the newspaper.
Ms Jardine told BBC Radio Scotland: "Like every other candidate I think it's important that we follow the advice and the rules of the Electoral Commission.
"The rules are there for a reason and I am confident that we have followed that advice, at all times.
"There was money which was allocated as having been spent on the national campaign, but that's because it was spent on a national campaign."
Edinburgh West was one of the toughest electoral battles in the election and a specific target for the Lib Dems.
The party had held on to the seat since 1997, but it was won by the SNP's Michelle Thomson in 2015 by 3,120 votes.
East Dunbartonshire MP Ms Swinson has also faced questions after thousands of pounds were omitted from her expenses as they were attributed to national spending and undelivered campaign materials.
Official declaration for the June election indicates her spending was £210 under the official limit of £14,619, The Herald reported on Thursday.
She said more than 93,000 leaflets and other material bought by the party at a cost of £2,700 were never used so could be omitted from the total, as could £4,040 which went on national spending promoting the party rather than her as a candidate.