Admin error caused funds misuse: Gichuhi

Liberal Senator Lucy Gichuhi has blamed an "administrative error" for the misuse of thousands of dollars of taxpayer funds.

Senator Gichuhi, who joined the Liberals in February, billed taxpayers more than $2000 to fly two family members to Adelaide in October last year for her 50th birthday.

"It was an administrative error and I know how inappropriate it was," Senator Gichuhi told ABC Radio on Monday.

"It was an error and as soon as we got to know of it we fixed it."

The freshly-minted Liberal has promised to repay the funds in full, but said she was still waiting for the appropriate government department to raise an invoice.

Senator Gichuhi entered the parliament last year after Family First's Bob Day was ruled ineligible to sit in the Senate.

She was elected in Mr Day's place because she had been Family First's second candidate on its SA ticket at the 2016 election.