UBS analysis suggests mortgage brokers are a relic of a previous age.

Research from UBS has found mortgage broker commissions increase the cost of the average home loan by 0.16 per cent - or $4,600.

The researcher used figures from a recent ASIC report into mortgage brokers, which calculated total commissions of $2.4 billion were paid in 2015 alone.

The figure comprised $1.4 billion worth of upfront commissions and another $1 billion in trailing commissions.

It was an 18 per cent increase on 2012 figures.

Research leader Jonathon Mott said mortgage brokers' fees were disproportionately high, given they were advising on a relatively simple product.

“We believe these payments are an illustration of excesses built into the financial system following a 26-year economic boom,” Mr Mott wrote in his report.

“While a mortgage is a large financial commitment, it is a simple, commoditised product.

“Options are relatively limited - fixed v variable, interest only v principal and interest, offset account - while APRA's focus on 'sound lending practices' ensures there should be little difference in underwriting standards or size of loan offered across the banks.”

The Mortgage and Finance Association of Australia says UBS got its figures wrong.

“It appears they have taken the total commission paid to brokers last year - which includes upfront and trail - and divided them only by the number of mortgages written by brokers last year,” MFAA chief executive Mike Felton told the ABC.

“This means they are comparing commissions on all loans written by brokers in the past 30 years to just the number of loans written last year.

“This has given them a commission per mortgage that is about double what it should be.”

The Australian Bankers' Association (ABA) recently called for greater transparency to reduce the risk of selling the wrong products.

An ABA report authored by former Australian Public Service Commissioner Stephen Sedgewick called for an overhaul of the payment structure for brokers.

It said volume-based incentives should be banned, and for temporary increases in commissions to boost sales and “soft-dollar” payments to be set up.

Mr Felton said the upfront commissions were not passed onto the consumer.

“The broker channel is an efficient way for lenders to originate loans as they do not carry the salary and branch costs associated with writing these loans,” he argued.

“Working with a customer to secure a mortgage is extremely complex and often requires months of work from a broker – not to mention years of service following as the broker supports the customer for the life of the loan.”

Mr Mott says the cost of commissions are factored into the banks’ cost of funding.

“These costs are borne by all mortgage customers,” he said.

“We estimate mortgage broker commissions add 16 basis points per annum to the cost of every mortgage in Australia, irrespective of whether the mortgage was broker or proprietary originated.”