Brendan Nelson has again been forced to defend himself after speculation over his future as opposition leader, saying he is determined to see the job through.

While conceding he faces a tough job in holding on to the Liberal leadership, Dr Nelson said he was "extremely confident" in his position.

"This is a job that is as hard as it is important and that's why I am determined to see it through and that's why I'll keep doing what I'm doing," he told ABC TV.

"These are hard days, hard yards, four-and-a-half months after an election with a change of government after almost 12 years," he said.

Everyone always knew and respects the fact that it's a challenging task, (but) I'm very confident in my position and I will continue to lead the opposition and to ensure we have effective, inspiring alternative policies for Australia."

Dr Nelson was emphatic in saying he had the numbers to retain the leadership, but refused to elaborate, preferring to shift the discussion to his much maligned "Listening Tour".

"I'm not going to speculate about any of those sorts of things," he said.

"The things that are of most concern to Australians is feeding, clothing and housing their children ... (getting their) kids into education, getting health care - all the things I've learned as I've gone (around) Australia over the last few weeks.

"I think the last thing people want is internal speculation about positions in the opposition."

-aap-ninemsn.com.au