The value of first-time buyer lending coming through intermediaries stood at just over half the market, or 53%, in the final three months of 2012.
In 2014 this figure jumped to 67%, then 74% in 2016, before hitting 77% in the final quarter of 2017.
Brokers have also steadily snatched a higher share of remortgages.
Lending that came through advisers has ticked up to 71% in the final quarter of 2017 from 68% in the same period of 2015.
The amount of home mover mortgages coming through brokers has stayed broadly flat at 69% at the end of 2017 from 68% in 2015.
A UK Finance spokesperson said: “We have seen a steady increase in mortgages sold by intermediaries to first-time buyers and home movers as the market remains buoyant.”
Brokers said the increase in regulation and complexities of the market are driving factors, as affordability calculations and lender criteria have become harder for consumers to understand.
Dominik Lipnicki, director at Your Mortgage Decisions, said: “I am not at all surprised that more and more clients are choosing to obtain their mortgage via an intermediary.
“For many clients, if they have to sit through a meeting with their local bank, they may as well do it with an adviser that has access to thousands of mortgage schemes.
“We find that clients value a personal service which is often missing from the high street, as the data shows, this is particularly the case with first time buyers who are facing the biggest financial commitment of their lives and want to ensure that the decisions that they make are fully informed and not rushed.”
Lenders say broker share has increased
The increase in lending coming through brokers is also a trend noted by lenders.
Charles Morley, director of mortgage distribution at Metro Bank, said: “We have seen the intermediary mortgage business grow significantly in recent years, as customers seek support and guidance in a market where product choice and complexity has increased at a similar rate.
“It’s important to allow customers choice throughout the mortgage process and often the support of a professional mortgage adviser is key to this.”
David Robinson, national intermediary sales manager at Accord, added: “Buying a home, especially your first, is one of the biggest financial commitments you can make.
“It’s clear that new homeowners appreciate the value of a broker who can guide them through the process, and provide quality advice on the best options available to them.”