Queensland Premier Anna Bligh says a controversial Christmas holiday stay at the house of her friend and former federal minister Ros Kelly was just "friends helping each other out".

Ms Bligh and her husband Greg Withers, a State Government bureaucrat, spent two weeks at the harbourside mansion of Ms Kelly, a lifelong friend of the premier and a Thiess board member.

The Premier did not record the stay on her Register of Members Interests, which requires parliamentarians to detail, amongst other things, gifts they receive and travel or accommodation paid for by someone else.

In a letter to the Speaker of Queensland Parliament, Mike Reynolds, Ms Bligh said she did not think the Christmastime stay was a gift "in the generally understood meaning of the word".

"While it was clearly an opportunity for my family and I to enjoy a private holiday in Sydney, where my husband comes from and where we have many relatives and friends, I saw the arrangement as nothing more than an opportunity for friends to help each other out," the letter states.

Ms Bligh said the stay was also not paid for by a third party and therefore did not need to be declared.

However, the Premier did ask that the Clerk of the Parliament to "record the relevant facts on the Register".

"While I believe that I have satisfied my obligations and that a declaration is unnecessary, I have no concerns with the fact of my family's holiday arrangements being in the public arena or on the Register of Members Interests," she wrote.

Ms Bligh was responding to a formal complaint the Queensland Opposition made in relation to the house-sitting arrangement.

The Premier also challenged Opposition leader Lawrence Springborg to declare his "regular trips" in the helicopter of a mining magnate.