No, users are redirected to the PayFast engine to complete their payments. The engine is hosted on the PayFast domain, therefore you can only track activity on your own domain up until the point where users are redirected to the PayFast engine to make a payment.
You can however record the transaction amounts and some other information related to products bought from your website. After a PayFast payment is completed via your domain, your merchant store is sent an ITN to confirm the payment and the buyer is redirected back to your payment success page. If you have Google Analytics' ecommerce tracking correctly set up across your entire website then your transactional data will be recorded in your Google Analytics account. This will not include activity in the PayFast Engine.