To date, Fairfax has reported on seven politicians who have recently repaid expense claims. There is Abbott (who repaid about $1700 for claims to attend the weddings of then colleagues Sophie Mirabella and Peter Slipper); Attorney-General George Brandis (repaid $1600 for claims to attend the wedding of radio personality Michael Smith); Agriculture Minister Barnaby Joyce (repaid $650 for a Commonwealth car to attend the same wedding); Labor MP Mark Dreyfus (repaid $466 he claimed for accommodation in Canberra when he was really on a skiing holiday), Immigration Minister Scott Morrison and Assistant Defence Minister Stuart Robert ($354 each for a wedding in 2011) and Western Australian Liberal MP Don Randall (repaid $5259 for claiming for ''electorate business'' a trip to Cairns with his wife.)

Joyce admitted he was wrong to claim for a car to take him to a wedding. Dreyfus said his claim was an ''administrative error''. Senator Brandis denies the claim was wrong, but said he repaid to ''resolve any ambiguity''. Abbott said he attended the weddings in an official capacity, admitted the rules were unclear and repaid the money ''to avoid doubt''. Morrison said it was an error, and Robert returned the money to avoid ''ambiguity''.

The exception is Randall, and it is his case that takes this story into more serious territory. He has so far provided no explanation for how his Cairns trip was for ''electorate business''. Fairfax reported that a week after his overnight November visit, he updated his pecuniary interest register to note that he and his wife had taken possession of a Cairns investment property, leading to the suspicion - only that at this stage - that this may have been the purpose of the visit. Randall paid back the money ''to ensure the right thing is done by the taxpayer and alleviate any ambiguity''. But that's far from good enough.

In the other instances, as much as they might fail the ''pub'' test, there is no suggestion of dishonesty or fraud, just stretching the rules a little, or a broad interpretation of ill-defined terms in a system that lacks oversight. Clearly something has to be done about that now, but if Randall's primary reason to travel to Cairns was to take possession of a house, that is something else entirely.

There is a well-known example of a former MP who was not allowed to pay back dubious expense claims. Former speaker Peter Slipper has been charged with three ''dishonesty'' offences after an Australian Federal Police investigation.