Am I correct in understanding that I should not declare the superannuation contribution on my tax return?

You are correct! However, you have to ensure that the administrator of your superfund correctly records it (i.e. it is recorded as a member contribution). When the superfund lodges their own annual return, they are obliged to lodge the MCS form.

The ATO use BOTH the MCS and your individual tax return to determine the co-contribution amount.

If you are self employed than you have to figure out how you made the tax deduction? If you made it and would like to claim a tax deduction for it, then you will not be eligible for the co-cont as it will be classified as a deductible contribution. If you do not claim a tax deduction for it and it is classified as an undeducted contribution then you will receive the cocontribution. You should really get some advice for this one and any future contributions. goto: www.ofp.net.au they have some great fact sheets

whether you declare it on your tax return, as long as it's a self super contribution, the government will know and as long as you're within the threshold eligible for the co-contribution, the government will automatically put in their part soon after that years' tax return's lodged.