While the federal government's deposit scheme has helped some first home buyers get into the property market, the time it takes to save a deposit has still blown out for others as the cost of entry-level properties surges, a new report shows. First home buyers are now facing a "dual affordability constraint", the report states, meaning deposits are taking longer to accumulate and repayments remain at near unaffordable levels for some once they've bought a property. The time required for a couple to save a 20 per cent deposit now ranges from two years and seven months for an entry-priced unit in Darwin to seven years and seven months for an entry-priced house in Sydney, according to Domain's latest study released on Thursday morning.