Storm clouds loom in Galle as Aussies eye more carnage

Australia is eyeing a convincing win in the Test series opener against Sri Lanka but rain is threatening to disrupt the visitors' charge on day three in Galle.

The covers first came out 15 minutes before lunch as rain began to fall, eventually washing out the entire second session.

It was quite the sight for the mostly Australian crowd in attendance, with Galle one of few Test cricket grounds where the entire outfield gets covered in wet weather.

It took a team of more than 50 workers to remove the heavy blue tarpaulins, weighed down by loose tyres and soaked from the downpour.

Tea was taken at 2:30pm local time, with 48 overs to be bowled in the third session from 2:50pm (8:20pm AEDT).

The covers were brought back out during the break with dark clouds threatening to cause further disruptions.

Earlier, Mitch Starc (2-13) and Matt Kuhnemann (2-48) disposed of Sri Lanka's strike weapon Kamindu Mendis and captain Dhananjaya de Silva as Sri Lanka went to lunch at 5-136.

The home side trailed by 518 runs on a pitch starting to offer assistance to the bowlers, with Australia needing one more wicket to expose Sri Lanka's tail.

Dinesh Chandimal (63no) offered resistance for the hosts, who had fallen to 3-44 at stumps on day two and were in desperate need of his positive intent.

The 35-year-old wore a bouncer from Starc on his hip and needed medical attention on the field but fought on for a 31st Test half-century.

He looms as the crucial wicket for Australia's bowling attack, having made his highest Test score - an unbeaten 206 - in the sides' last meeting in Galle in 2022.

Kusal Mendis (10no) is unbeaten next to Chandimal.

But teammates Kamindu Mendis and de Silva threw their wickets away earlier in the first session.

Starc did well to extract some swing from the ball during the session and enticed Mendis into poking down the leg-side, where he was caught by Alex Carey.

Mendis (15) had scored five centuries last calendar year, including an unbeaten 182, the last time Sri Lanka hosted at Galle in September, against New Zealand.

De Silva (22) advanced on Kuhnemann but missed the left-arm offspinner's length ball and found himself stumped by Carey.

Axed from the Test side for the series opener, Sam Konstas watched the third day's play from the team hotel after coming down with a stomach bug. Team officials were confident the issue was not serious.

Australia confirmed legspinner Tanveer Sangha would join the Test squad in Galle as their second development player after Ollie Peake, but is not expected to be considered for selection.