Steve Smith scored an unbeaten 85 to guide Australia to 339-5 as England wasted favourable bowling conditions on the first day of the second Ashes Test at Lord's on Wednesday.

England captain Ben Stokes won the toss under grey skies and floodlights at the home of cricket, sending Australia into bat with high hopes of taking early wickets in his team's bid to level the series.

But David Warner and Usman Khawaja rode their luck to share a gritty opening partnership of 73 and although Josh Tongue removed them both, Marnus Labuschagne made 47 and Travis Head a rapid 77 to put Australia in a commanding position.

Joe Root removed Head and Cameron Green in the same over to give England late hope but the day firmly belonged to Australia.

The game was disrupted after one over when two Just Stop Oil protesters ran on to the pitch and sprayed orange powder on to the outfield but Warner and Khawaja were not distracted.

They negotiated probing spells from James Anderson and Stuart Broad and, after a short rain delay, Warner reached his fifty by hooking Tongue for six before Khawaja was bowled by the same bowler for 17 just before lunch.

Each batsman was dropped in the slips, Khawaja offering a very difficult chance to Root and Warner a sharp one to Ollie Pope.

Warner lived dangerously after lunch too, particularly against Tongue who continued his impressive spell by bowling the left-hander through the gate for 66 with a fine swinging delivery to reduce Australia to 96-2.

Smith emerged from the pavilion to a chorus of boos but he settled down quickly and silenced the crowd with two sumptuous drives off Broad to the cover boundary.

Broad almost exacted swift revenge when Smith was given out caught by wicketkeeper Jonny Bairstow in the same over for 24 but the batsman reviewed and the decision was overturned.

Labuschagne started slowly before finding his rhythm with three fours off one Broad over and when Stokes brought himself on to bowl the Australian right-hander stroked him to the boundary three times.

Broad thought he had trapped Labuschagne lbw, the umpire raising his finger before the batsman was reprieved, but the Australian departed shortly after tea, feathering a catch to Bairstow off Ollie Robinson.

Head joined Smith and accelerated the scoring rate as the England bowlers tired in the final session.

Smith passed fifty and Head reached his half-century off only 48 balls, the pair peppering the boundary rope all around the ground.

Head was stumped off Root by Bairstow after scoring 77 off 73 balls and three deliveries later Cameron Green aimed an ugly swipe at the spinner to give Anderson a simple catch at mid-off.

It was a positive end to a poor day for England in which Stokes looked short of ideas and used few of the innovative field settings which have been a feature of his captaincy.

He bowled only three overs and England's hopes of winning back the Ashes are fading after six days of the series.