Despite losing almost three hours due to wild weather on Tuesday, the tourists managed to send down 66 overs to Australia in front of 62,167 spectators at the MCG after Pakistan captain Shan Masood won the toss and elected to bowl first.

A watchful Marnus Labuschange (44 not out from 120 balls) will return to the crease on Wednesday with Travis Head (9 not out), who copped a flying ball to the shoulder thanks to an accidental full toss from Pakistani quick Shaheen Afridi.

Play started on time on Tuesday as the sun shone brightly, but the skies quickly got dark after lunch and players went off the ground midway through the second session.

Spectators were warned via the scoreboards to prepare for severe weather and "seek shelter from exposed areas" as the MCG lights were turned on in the early afternoon.

After being off the field for 170 minutes, players returned for almost two hours as play was extended for a further 90 minutes beyond the scheduled stumps time.

Pakistan secured a crucial breakthrough during that period, with Aamer Jamal dismissing out-of-sorts star Steve Smith (26), who successfully reviewed a lbw shout that was given out by the on-field umpire when he was on 19.

But Pakistan's day should have been so much better after openers David Warner and Usman Khawaja put on a 90-run stand to make the tourists pay for some sloppy fielding.

Masood was left deflated when Abdullah Shafique put down Warner at first slip off the last ball of Afridi's second over.

Warner, who smashed 164 in the first Test in Perth, was on two when Shafique dropped a catch that left former Australia coach Justin Langer stunned.

"That's as easy a catch that you'll ever see in Test cricket," Langer said in commentary on the Seven Network.

Warner was out for 38 to part-time spinner Agha Salman (1-3) on the final ball before lunch, giving Pakistan some badly-needed confidence.

"Another wicket less would have been great, but credit to the way Pakistan bowled. They bowled unbelievable channels," Warner said.

"The way (Mir) Hamza bowled around the wicket at the end there it was like bowling with a Duke ball."

After a promising start, Khawaja was dismissed for 42 after playing a poor shot off Hasan Ali's (1-21) bowling early in the middle session.

Khawaja had hoped to use images of a dove holding an olive branch, as well as a reference to an article one of the Universal Declaration of Human Rights, during the Boxing Day Test to show his support for those suffering during the ongoing conflict in the Middle East.

Instead, Australia's opener walked out to bat on Boxing Day with the names of his children, Aisha and Ayla, written on his shoes.

The MCG pitch has produced bowler-friendly conditions since the infamous dull drawn Ashes in 2017, which is why Masood chose to bowl first.

Pakistan quicks Afridi, Jamal, Mir Hamza and Hasan Ali were able to produce significantly more swing and seam movement than they did in Perth, where they lost the first Test of the Benaud-Qadir series by 360 runs.

"We are a bit (unlucky) we haven't got enough wickets but the best thing is we did not give them enough runs," Ali said.

"So I think we are a bit ahead of them."

Australian Associated Press