Does Oxford ever waive the IELTS language requirement?
This is not very specific, I thought you were referring to undergraduate but if you have 4 peer-reviewed publications already then I guess you must be at least PhD level?

In the former case, in my experience Oxford University does not waive the requirements for English and you are probably better off if you take the test again. By the way, my understanding is that you need a 7.0 average AND at least 7.0 in each component.

If you are applying for something more senior (PhD, Postdoc, etc) then it depends on the individual department at which you'd be working.

-edit-
Aah, just seen you tagged this with PhD. The requirements you list (7.0 ave + 6.5 component minimum) are for a Master's degree rather than the DPhil.
To my knowledge the IELTS requirements vary by department (mine doesn't seem to have any, for instance) but it looks like a 7.5 average with no less than 7.0 in any one component is the most common requirement. Based on that you will definitely have to resit the IELTS exam.

You can see the generic requirements here: http://www.ox.ac.uk/admissions/graduate/applying-to-oxford/application-guide#content-tab--3
For a DPhil the 'higher level' requirements would be needed, if applicable to your subject.