The average house purchase deposit jumped 15% in a year to more than £80,000 in December.
This is its highest point since the National Mortgage Index from Mortgage Advice Bureau was launched in 2009.
The average LTV has fallen to it lowest level since June 2010 as borrowers put down higher deposits.
Affordability has worsened as house prices rise 9.3% annually while salaries fall 2.9%, it said.
The average purchase price for a property in December rose to £252,990, up from £231,487 one year earlier.
The typical buyer’s LTV fell to 68.2% in December, the lowest since June 2010, as borrowers shoulder more of the cost of their house purchase themselves.
Brian Murphy, head of lending at Mortgage Advice Bureau, said: “An inevitable repercussion of rising house prices is that higher deposits are required.
“Those who cannot afford to put up more may find their choice of properties limited.”
Murphy said the housing market is yet to come off the boil despite the current dearth in property supply.
“As a result house prices are likely to continue rising this year, bringing about affordability concerns that will particularly affect first-time buyers.
“A significant boost to the construction of new homes is needed to prevent some buyers being priced out of the property market.”