Qatar Airways has joined Gulf neighbours Emirates and Etihad in letting travellers pay their way into its Doha airport lounges even if they're not flying in business class.

The airline has pegged entry to its opulent Al Mourjan business class lounge (below) at 450 Qatari Riyals, or A$165.

The sprawling Al Mourjan lounge is the size of 10 Olympic swimming pools and spread across two storeys, which are connected by a grand spiral staircase astride an eye-catching infinity pool water feature.

However, paid entry is limited to passengers on Qatar Airways flights booked by the airline – travellers on codeshare flights and Oneworld partners such as British Airways need not apply. (Tickets booked on frequent flyer points also don't make the cut.)

Read the AusBT lounge review: Qatar Airways Al Mourjan business class lounge, Doha Hamad Airport

A flash of cash will also open the door at the airline's designated lounges for Oneworld frequent flyers travelling in economy.

The 'First Class' lounge for Oneworld Emerald members – including Qantas Platinum and BA Executive Club Gold – lists at QAR300 (A$110), with the 'Business Class' lounge for Oneworld Sapphire members (including Qantas Gold and BA Executive Club Silver) at QAR250 (A$92).

However, unlike Emirates and Etihad, entry to Qatar's Al Safwa first class lounge remains restricted to actual first class flyers.

Also read: Is Emirates' Dubai business class lounge worth $100 to visit?