Vacancy rates have remained tight, suggesting tenants currently face a gruelling task in finding rental properties across much of Australia.

SQM Research figures show the national vacancy rate remained steady at 1.8% for May, with vacancies up only 0.2% for the year.

No capital cities saw increased vacancies for the month, and vacancies dipped slightly in Brisbane, Darwin and Hobart.

"Darwin is now beginning to show obvious signs of an extremely tight rental market, dropping again to 0.4% during May, coming to a total of only 100 listings,” SQM said.

The data provided added that Melbourne continues to sit on the opposite side of the spectrum, again recording the highest vacancy rate among capital cities at 3.1%. Melbourne also had the highest level of residential vacancies, coming to a total of 11,427.

SQM managing director Louis Christopher said vacancy rates were unlikely to ease in the near future.

"For many months now, vacancies across most of the country have remained very low ensuring that competition is fierce between prospective tenants, particularly at the affordable end of the market.

“As we have continually stated, we see no relief on that front, other than in Melbourne where there is still many more dwellings coming onto the market this year," he said.