The latest CoreLogic figures are likely to show price growth flat-lined in April with Sydney having its first monthly decline since December 2015.
Full-month figures due to be released on Monday will show the country's peak growth phase has possibly paused or passed.
CoreLogic head of research Asia Pacific Tim Lawless noted the CoreLogic hedonic home value index has virtually held steady over the first twenty-seven days of the month for the five city aggregate index, "with a subtle fall in Sydney values over the month to date."
"Recent regulatory changes aimed at slowing the pace of investment and interest-only lending have pushed mortgage rates slightly higher and slowed the pace of investment demand. These changes appear to be having a dampening effect on housing market conditions."
" The softer results come after a strong re-acceleration in home values that has been evident through the second half of 2016 and the first quarter of 2017.
"Recent regulatory changes aimed at slowing the pace of investment and interest-only lending have pushed mortgage rates slightly higher and slowed the pace of investment demand.
"These changes appear to be having a dampening effect on housing market conditions."
The figures had Sydney up 1.4 percent in March - up 18.9 percent over the 12-month period.
The last decline in Sydney values came in the December quarter of 2015, with a 1.4 percent decline in November and a 1.2 percent fall in December, coinciding the first round of credit curbs.
Monday's report will include figures for the five mainland capitals.
