I am only guessing that you might have a fairly light, sandy soil? In my old garden I had light soil, and the iris rhizomes used to pull themselves down into it. It was not really a problem, except that the dwarf beardeds used to almost disappear.
You could put the fork in underneath the clump and lift it slightly, but you may cause disturbance to the roots. You would probably do just as well to loosen the soil around them clump to provide good drainage. If your soil is fairly light it won't be a problem, but in heavy soil you have 2 problems - one of drainage if they get wet. You could end up with rotting rhizomes. The other problem is access of the rhizome to sunlight, for warmth. In most parts of Australia the sun is warm enought to heat up the rhizome through a couple of inches of soil, to enable flowering. In fact it is often better to cover the rhizome a little to prevent sunburn in some areas.
You could feed your irises later this month with a general fertiliser for good flowering. Sulphate of potash is good for root production - you should get some idea of how far the roots have spread when you weed and cultivate. I generally only apply lime June/July, and a general purpose, roughly 6:6:6 NPK fertiliser, in late August, and again after flowering, if I remember.
I also prepare new beds with well rotted cow manure, gypsum and superphosphate.

Thanks Sparaxis for your advice. I'll try loosening the soil for drainage. I did notice that some of the ends of the iris have started to rot. Should I try to slice this rot off with a knife leaving the iris in the soil? Will this rot affect flower production this season? Would you need to dust the end of the iris with anything if you do cut off the rot?

Do you use a formula for how much cow manure to gypsum and superphospate? I have been spreading the cow manure recently thinking my roses would enjoy this. My iris have really sprung to life in the last two weeks. There is quite a difference in the state of my iris between the back and front garden. The back is in sandy soil with no rot but the front is in a newly established garden where there has been more mulch and leaves. Thanks again for your assistance.

If you cut the ends of the rhizomes off they will most likely rot right through, once the inside is exposed to damp. Lime is the best thing to put on the open ends, and you can use this at this time of year, but it will inhibit the uptake of fertiliser, so you do so at the expense of bloom.
When I lime my irises in winter it looks like a snowstorm - i am very heavy handed, but I have quite acid soil here, and quite wet heavy clay loam. By adding sand and gypsum and building my beds up considerably higher than they were, i think I may have escaped rot this year. I should mention that my iris beds are built on a flat area over the top of the septic drainage beds, so i have a particularly difficult situation.
You don't say whether your soil is sandy or heavy? Do you have some idea of the acidity? You can use dolomite instead of garden lime, and it does not change the pH as much.
I don't use any formulas, just a general idea - for a bed 2 railway sleepers (9ft) long and 1 sleeper wide, I added a small trailer load of sand and 1/2 of manure. Gypsum had to be put on quite heavy - probably 1/4 cm thick all over. Then I rotary hoed it all in, and mounded the soil in rows - 6 rows across each bed roughly 60cm wide, with a depression between of course. Each raised row is planted with a double row of bearded iris - I fit around 80 clumps to each large bed.
To cut back on weeding I filled the depression with pea straw, which does unfortunately harbour fungal spores and contribute to leaf spotting, but it is easier to strip off than bark chips, when I re-make the bed.
I also rotate my iris beds with vegetable beds. I find this is helping considerably. 2 years with irises, 1 with vegies.
Doesn't work with everyone of course, because of the space needed. I am working more towards growing my irises in with other plants, but with over 500 varieties, that is not an easy option for me.

Thanks again for your great advice. I have not tested the PH so will get a kit. The front garden is heavy soil but the back is quite sandy. I think I will leave the rot and enjoy the flowers but your advice on the lime was new knowledge for me. How wonderful to enjoy October with 500 iris. Every year I try to make it to Pearcedale to see Tempo2.
It was most interesting to read your rotation methods and approach to building new beds. (I had better hold back from the very tempting idea to rotary hoe my back lawn and provide some jumping obstacles for our dog.)

I was looking at one of the American websites and they were nominating the double bloomers. Have you had much success with this? Do you have to change your fertilising regime or is success a bit dependent on your own specific soil/climate etc.(as well as wise choices). Maybe the Iris Newsletter could give some advice on this for novices, like myself. Thanks again for the tips. Sebd

Many of Barry Blyths irises will rebloom if given the right conditions. You have to water them through summer, which is no good to me, with phase 3 restrictions and a big garden. I got into irises because they are extremely drought hardy. You also have to feed them more as they increase quickly. Dividing and replanting can be a problem as you never know if they are planning a rebloom or not. Some simply "rebloom" in Autumn, but don't bloom in Slring/Summer, but that's Ok as that's when you don't normally have them. I get the odd bloom stalk in Autumn, usually only 2 or 3 each year, and coinciding with the first frosts, so i have to pick them and bring them in, and only get a couple of blooms. In general I can't be bothered with them. Instead i get my "kicks" from growing a lot of species iris and extending my bloom season well into January with those. Then I enjoy my roses :-)

Just a quick reply about sulphate of potash - after asking an iris growing friend. You can apply it in the next few weeks, at the same time as a general purpose fertiliser.
If anyone is interested, the Victorian Iris Society show is on Sunday the 30th October (Melb cup weekend) from 11.00am to 4.00pm. $4.00 admission, children free.
There will be a wonderful display of irises of all varieties, an iris auction every hour on the hour, and a huge sale of donated iris rhizomes, mostly tall beardeds.
I will be one of the ladies selling rhizomes - if you want to meet me ask for Jan Clark.

Thank you for the follow-up on the sulphate of potash. Is the Iris Show at Mt Waverley Community Centre?

yes - sorry I didn't put that. I have put a notice up on the general gardening forum. Melways reference 70, E1