Australia fast bowler Glenn McGrath says Pakistan paceman Shoaib Akhtar is a showman whose main goal is simply to bowl quicker than anyone else in Test cricket history.

McGrath told reporters on Thursday that Shoaib should consider reducing his run-up to help Pakistan's chances of beating Australia in the second Test starting in Melbourne on Sunday.

"He (Shoaib) talks it up pretty well, like saying a jet needs a run-up before it can take off," said McGrath, who has taken 472 wickets.

"My goal has always been to be the best bowler in the world, not so much the quickest.

"I'm sure Shoaib's major and only goal is to be the quickest bowler in the world, if not of all time."

Pakistan lost last week's first Test in Perth by 491 runs. Shoaib took six wickets but was criticised for taking more than six minutes to bowl an over and for tiring after short spells.

Pakistan coach Bob Woolmer said this week he had given up on attempts to convince Shoaib to shorten his run-up.

"When you are bowling six-and-a-half minute overs it puts pressure on the other guys to get through their overs, plus you can only get through three or four at top pace before you start feeling the pinch," McGrath said.

"He could bowl just as quick off a shorter run. They say it is 33 metres. Mine is 23 metres and he looks a good 17 or 20 metres behind me."

McGrath said Shoaib may find a shorter run-up did not feel right, in which case it was best to stick with the longer version.

"If he prefers that, they have to look at other ways how they can get through their overs," McGrath said.

"There is probably no bigger bowler in world cricket who is more of a showman.

"That's what he loves. Cutting that run-up down might take a bit away from who he is, so maybe that's why he's holding on.

"He's a top bowler who can just rip through sides. But he also has the potential to bowl a heap of rubbish as well."