Speaker Bishop finally apologises

Speaker Bronwyn Bishop has finally apologised for taking a $5000 helicopter ride from Melbourne to Geelong to attend a Liberal Party fundraiser.

But she insists she will not resign over the expenses scandal that has engulfed the veteran MP and Abbott government.

"I want to apologise to the Australian people for my error of judgment and to say sorry," a contrite Mrs Bishop told 2GB on Thursday.

"I feel I've let them down."

Mrs Bishop has pledged to repay all expenses related to her travel to the weddings of Liberal colleagues.

But she insists her claiming of taxpayer-funded travel allowances to attend the weddings of Sophie Mirabella and Teresa Gambaro was "technically in the rules".

She's also asked the prime minister to have all her expenses investigated by the Finance Department.

Mrs Bishop said there was no excuse for taking the $5000 helicopter ride.

She also admits she should have apologised earlier but insists she won't step down from her role as speaker.

"I know that I've disappointed and let down the Australian people," Mrs Bishop said.

"I won't be resigning."

Independent MP Clive Palmer, who is expected to move a no-confidence motion against the Speaker when parliament resumes in August, accused Mrs Bishop of "complete bias" in the role.

"She needs to go," he told the Seven Network.

"We are sick of our politicians with their snout in the trough."

Labor expects Mrs Bishop to step down before parliament resumes on August 10.

Opposition Leader Bill Shorten said the government would be compromised if it didn't act soon.

"They hope that the whole thing will move on - but it's been lodged in the minds of the Australian people," he told ABC radio.