"Resigning from a role
An employee should make it clear that they are formally resigning. It would be best to do this in writing, giving the correct amount of notice. Employees who have at least one months service must give one week's notice unless a longer notice period is required in their contract of employment."
"Dismissing an employee
Employers usually must give employees at least the notice stated in the contract of employment or the legal minimum notice period, whichever is the longer. The legal minimum notice required to dismiss is:
one week if the employee has been employed between one month and two yearsone week for each complete year of employment up to a maximum of twelve weeks. For example, for two years continuous employment the notice period will be two weeks, for six years continuous employment the notice period will be six weeks."
Although the Act you are looking at does include employment contracts, the notice periods are legal as they are at least the minimum periods required and clearly stated in the contract.