According to data from market analyst CACI, £17bn of mortgages will mature in September and a further £18bn will mature in October.
The two-month period is part of a hectic 18 months which is expected to see a total of £350bn of product maturities.
Lender Accord urged brokers to contact their clients as the current competition in the remortgage market meant they could potentially save hundreds of pounds a month.
Accord national intermediary sales manager David Robinson said: “Brokers have an important role to play in advising and helping their clients understand whether now could be the best time to remortgage.
“It’s a good opportunity for brokers to start a conversation with anyone who is coming to the end of the fixed rate on their mortgage, to examine whether they would benefit by fixing now while market conditions are still extremely favourable to borrowers.”