Although you possibly can get a home loan while on maternity leave, lenders may see you as a riskier borrower because your income is reduced. This means you would not be able to borrow as much as you would on a full income.
There are a few things you could do to improve your chances of being approved:
Get documention from your employer detailing the terms of your maternity leave, such as the dates and your salary upon your return.
Save at least a 20% deposit.
Set a realistic budget and loan amount.
Talk to multiple lenders before applying. Too many rejected applications will look bad on your credit report, so be sure you get the answers before you apply.
Consider talking to a mortgage broker.
If you want to increase an existing home loan, you may be able to do this while on maternity leave. The increase would need to be a reasonable amount with a lender who will accept you and you can prove that you can afford it.