Answer:
If an employee refuses to sign an employment contract until certain changes are made then a verbal contract will still exist between the employer and the employee while contractual negotiations are underway. The National Employment Standards apply to all employment arrangements whether or not it is in writing. The contract must comply with National Employment Standards and you should be wary if any of the clauses in dispute are actually entitlements, which cannot be altered.
If the agreed to employment contract is breached, both the employer and employee have rights under contract law. The employee is unlikely to be eligible to apply for unfair dismissal, as employees must have been working for an employer for at least 6 months or 12 months (depending on whether it is a small business) to be eligible.