It depends on how many new shares are created.
If you want to keep the same percentage of shares in the company, you should buy an amount equal to the percentage you already own.
For example, if there are 400 total shares and you own 4, you own 1% of the company. If 100 new shares are created, you now own 0.8%. If you buy 1% of the 100 new shares (1), you will continue to own 1%.
Is this what you are asking?