The average five-year fixed-rate deal is now 2.91 per cent, just 0.41 per cent higher than a two-year equivalent at 2.5 per cent, according to Moneyfacts.co.uk.
The gap has shrunk from 0.64 per cent in 2016 and from 0.44 per cent in 2018, taking it to the lowest level since 2013 when it was 0.27 per cent.
It comes after a number of big lenders sliced mortgage rates in January.
Moneyfacts spokeswoman Rachel Springall said: “While economic uncertainties could potentially put off home movers this year, it is still vital that the market keeps moving, or it could cause a standstill.
“Lenders must consider their levels of risk while also keeping rates low to pull in both buyers and remortgage customers.
“As the two-year fixed market becomes saturated with cheap deals, lenders will no doubt make efforts to compete on five-year deals.
“While it is difficult to predict what the mortgage market may face in 2019, it is still positive to see the rate gap shrink, particularly for those borrowers eyeing up a five-year fixed deal who want to avoid any potential interest rate rises for some peace of mind.”